Conjugates of hydroxyalkyl starch and a protein

ABSTRACT

Conjugates of hydroxyalkyl starch and a protein are provided herein. The conjugates are formed by a covalent linkage between the hydroxyalkyl starch or a derivative of the hydroxyalkyl starch and the protein. Methods of producing the conjugates and the use of the conjugates also are provided herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 11/518,558, filed Sep.8, 2006, now U.S. Pat. No. 8,017,739, which is a continuation-in-partand claims benefit under 35 U.S.C. §120 of International Application No.PCT/EP2005/002637 having an International Filing Date of Mar. 11, 2005,which published in English as International Publication Number WO2005/092390, and which claims the benefit of priority of U.S.Provisional Application Ser. No. 60/552,174, filed on Mar. 11, 2004,European Application Serial No. 04005849.7, filed on Mar. 11, 2004,Argentinian Application Serial No. P20040102853, filed on Aug. 9, 2004,and International Application No. PCT/EP2004/008821, filed on Aug. 6,2004.

TECHNICAL FIELD

The present invention relates to conjugates of hydroxyalkyl starch and aprotein, wherein the conjugates are formed by a covalent linkage betweenthe hydroxyalkyl starch or a derivative of the hydroxyalkyl starch andthe protein. The present invention also relates to the method ofproducing these conjugates and the use of these conjugates.

BACKGROUND

It is generally accepted that the stability of proteins can be improvedand the immune response against these proteins is reduced when theseproteins are coupled to polymeric molecules. WO 94/28024 discloses thatphysiologically active proteins modified with polyethylene glycol (PEG)exhibit reduced immunogenicity and antigenicity and circulate in thebloodstream considerably longer than unconjugated proteins, i.e. have areduced clearance rate.

WO 02/09766 discloses, among others, biocompatible protein-polymercompounds which are produced by conjugation of biologically activeprotein with a biocompatible polymer derivative. The biocompatiblepolymers used are highly reactive branched polymers, and the resultingconjugates contain a long linker between polymer derivative and protein.As biocompatible polymers, polymers of formula(P—OCH₂CO—NH—CHR—CO—)_(n)-L-Q_(k)-A are described, wherein P and Q arepolymeric residues and k may be 1 or 0. For P and Q, polyethyleneglycol, polypropylene glycol, polyoxyethylene, polytrimethylene glycol,polylactic acid and its derivatives, polyacrylic acid and itsderivatives, polyamino acid, polyvinyl alcohol, polyurethane,polyphosphazene, poly(L-lysine), polyalkylene oxide, polyacryl amide andwater soluble polymers such as dextran or polysaccharide are mentioned.As proteins, among others, alpha, beta and gamma interferons, bloodfactors, cytokines such as interleukins, G-CSF, GM-CSF are mentioned. Inthe examples of WO 02/09766, only mono-, di- and tri-polyethyleneglycolderivatives are disclosed which are coupled exclusively to interferonand epidermal growth factor, and human growth hormone.

WO 94/01483 discloses biocompatible polymer conjugates which are formedby covalently binding a biologically inactive polymer or polymerderivative to a pharmaceutically pure, synthetic hydrophilic polymer viaspecific types of chemical bonds. As naturally occurring polymers andderivatives thereof, polysaccharides such as hyaluronic acid,proteoglycans such as chondroitin sulfates A, B and C, chitin, heparin,heparin sulfate, dextrans such as cyclodextran, hydroxyethyl cellulose,cellulose ether and starch, lipids such as triglycerides andphospholipids are disclosed. As synthetic polymers, among others,polyethylene and derivatives thereof are described having an averagemolecular weight of from about 100 to about 100,000. As proteins linkedto the polymer or the polymer derivative, cytokines and growth factorsare described, including interferons, tumor necrosis factors,interleukins, colony stimulating factors, growth factors such asosteogenic factor extract, epidermal growth factor, transforming growthfactor, platelet derived growth factor, acidic fibroblast growth factorand others are disclosed. In all working examples of WO 94/01483,polyethylene glycols derivatives are used as polymer.

WO 96/11953 discloses N-terminally chemically modified protein compoundsand methods of their production. Specifically, G-CSF compositions aredescribed which result from coupling a water soluble polymer to the Nterminus of G-CSF. In the context of WO 96/11953, also consensusinterferone N-terminally coupled to water soluble polymers aredisclosed. While a wide variety of water polymers are listed in WO96/11953 (e.g. copolymers of ethylene glycol and propylene glycol,carboxymethyl cellulose, dextran, polyvinyl alcohol, polyvinylpyrrolidone, poly-1,3-dioxolane, poly-1,3,6-trioxane, ethylene/maleicanhydride copolymer, polyaminoacids (either homopolymers or randomcopolymers), poly(n-vinyl pyrrolidone)polyethylene glycol, polypropyleneglycol homopolymers, polypropylene oxide/ethylene oxide copolymers orpolyoxyethylated polyols), only PEGylated G-CSF or consensus IFNcompositions are described in the working examples of WO 96/11953.

WO 97/30148 relates to polypeptide conjugates with reduced allergenicitycomprising a polymeric carrier molecule having two or more polypeptidemolecules coupled thereto. These conjugates are preferably part ofcompositions used in the personal care market. Said conjugates areproduced by activating a polymeric carrier molecule, reacting two ormore polypeptide molecules with the activated polymeric carrier moleculeand blocking of residual active groups on the conjugate. As polymericcarrier molecule, a vast variety is listed in WO 97/30148, includingsuch different groups of compound like natural or synthetic homopolymerssuch as polyols, polyamines, polycarboxylic acids and heteropolymerscomprising at least two different attachment groups. Examples are given,which comprise star PEGs, branched PEGs, polyvinyl alcohols,polycarboxylates, polyvinylpyrrolidones and poly-D,L-amino acids. Amongothers, also dextrans such as carboxymethyl dextran, celluloses such ashydroxyethyl cellulose or hydroxypropyl cellulose, hydrolysates ofchitosan, starches such as hydroxyethyl starches or hydroxypropylstarches, glycogen, agarose, guar gum, inulin, pullulan, xanthan gum,carrageenin, pectin, alginic acid etc. are disclosed. As polypeptides,only some enzymes are explicitly disclosed.

Baldwin, J. E. et al., Tetrahedron, vol. 27 (1981), pp. 1723-1726describe the chemical modification of dextran and hydroxyethyl starch togive aldehyde substituted polymers which are allowed to react withhemoglobin to give soluble polymer-bound hemoglobins. These were shownto be capable of binding oxygen, but heart perfusion experiments clearlyindicated that the polymer-bound hemoglobins were not suitable for useas blood substitutes.

WO 99/49897 describes conjugates of hemoglobin formed by reactingpolysaccharides such as dextrane or hydroxyethyl starch with aminogroups of the hemoglobin. As functional groups of the polysaccharide,aldehyde groups produced by oxidative saccharide ring-opening are used.As preferred reducing agent used, borane dimethylamine is disclosed.Moreover, WO 99/49897 is exclusively limited to hemoglobin.

WO 03/074087 relates to a method of coupling proteins to astarch-derived modified polysaccharide. The binding action between theprotein and the polysaccharide, hydroxyalkyl starch, is a covalentlinkage which is formed between the terminal aldehyde group or afunctional group resulting from chemical modification of said terminalaldehyde group of the hydroxy alkyl starch molecule, and a functionalgroup of the protein. As reactive group of the protein, amino groups,thio groups and carboxyl groups are disclosed, and aldehyde groups ofthe protein are not mentioned. Moreover, while a vast variety ofpossibilities of different linkages is given in the form of many lists,including different functional groups, theoretically suitable differentlinker molecules, and different chemical procedures, the workingexamples describe only two alternatives: first, an oxidized hydroxyethylstarch is used and coupled directly to proteins usingethyldimethylaminopropyl carbodiimide (EDC) activation, or anon-oxidized hydroxyethyl starch is used and coupled directly to aprotein forming a Schiff's base which is subsequently reduced to therespective amine. Thus, the working examples of WO 03/074087 neitherdisclose a single conjugate coupled via a thio group or a carboxy groupof the protein, nor describe a conjugate comprising hydroxyethyl starch,the protein, and one or more linker molecules.

Nearly the complete literature regarding techniques of coupling apolymer to a protein describes PEGylation methods and PEGylated proteins(e.g. interferons alpha, interferons beta). Despite the progress ofcoupling methods and use of monofunctional PEG-molecules, a generaldisadvantage of PEGylated drugs is that the metabolization pathway ofPEG as a non-natural polymer is not known in detail.

Some of the patents describe the modification of interferon bysubstitution of amino acids, increased glycosylation or formation ofmultimers. These methods require high technological efforts (recombinanttechniques) and could result in new entities which are markedlydifferent from the natural proteins (e.g. interferon) and could exhibitdifferent properties.

Moreover, it is taught in the art describe to form, e.g., of complexesbetween IFN-beta and polysaccharides via metal complexation. However,complexes are not as stable as covalent conjugates and contain metalions (e.g. Zn²⁺), which might have undesired side effects.

SUMMARY

Thus, it was an object of the present invention to overcome the abovementioned drawbacks of these conjugation techniques and to provideinterferon beta conjugates based on a well defined, biodegradable, watersoluble polymer, which is covalently coupled to the protein.

It was another object of the present invention to overcome the abovementioned drawbacks of these conjugation techniques and to provideinterferon alpha conjugates based on a well defined, biodegradable,water soluble polymer, which is covalently coupled to the protein.

It was yet another object of the present invention to overcome the abovementioned drawbacks of these conjugation techniques and to provide ATIII conjugates based on a well defined, biodegradable, water solublepolymer, which is covalently coupled to the protein.

It was still another object of the present invention to overcome theabove mentioned drawbacks of these conjugation techniques and to provideGM-CSF conjugates based on a well defined, biodegradable, water solublepolymer, which is covalently coupled to the protein.

It was yet a further object of the present invention to overcome theabove mentioned drawbacks of these conjugation techniques and to provideA1AT and/or tPA and/or APC and/or and/or Factor VII and/or Factor VIIIand/or factor IX conjugates based on a well defined, biodegradable,water soluble polymer, which is covalently coupled to the protein.

It is a further object of the present invention to provide methods ofproducing these conjugates.

In one aspect, this document features a method for preparing a conjugatecomprising a protein and a polymer or a derivative thereof, wherein thepolymer is a hydroxyalkyl starch (HAS). The method can include reactingat least one functional group A of the polymer or the derivative thereofwith at least one functional group Z of the protein and thereby forminga covalent linkage, wherein Z is selected from the group consisting ofan amino group, a thiol group, an aldehyde group and a keto group, and

-   -   wherein, when Z is an aldehyde group or a keto group, A        comprises an amino group forming the linkage with Z, and the        protein is selected from the group consisting of IFN beta,        GM-CSF, APC, tPA, A1AT, AT III, factor VII, factor VIII, and        factor IX,    -   wherein, when Z is an amino group, A is selected from the group        consisting of a reactive carboxy group and an aldehyde group, a        keto group or a hemiacetal group, and wherein the protein is        selected from the group consisting of IFN alpha, IFN beta,        GM-CSF, APC, tPA, A1AT, AT III, factor VII, factor VIII, and        factor IX,    -   wherein, when A is an aldehyde group, a keto group or a        hemiacetal group, the method further comprises introducing A in        the polymer to give a polymer derivative    -   by reacting the polymer with an at least bifunctional compound,        one functional group of which reacts with the polymer and at        least one other functional group of which is an aldehyde group,        a keto group or a hemiacetal group, or is a functional group        which is further chemically modified to give an aldehyde group,        a keto group or a hemiacetal group, or    -   by oxidizing the polymer to give at least one aldehyde group, in        particular at least two aldehyde groups, or    -   wherein, when A is a reactive carboxy group, the method further        comprises introducing A in the polymer to give a polymer        derivative    -   by selectively oxidizing the polymer at its reducing end and        activating the resulting carboxy group, or    -   by reacting the polymer at its non-oxidized reducing end with a        carbonic diester, or    -   wherein, when Z is a thiol group, the protein is selected from        the group consisting of IFN alpha, IFN beta, tPA, A1AT, APC,        factor VII and factor IX, and A comprises    -   a maleimido group or    -   a halogenacetyl group

forming the linkage with Z.

The hydroxyalkyl starch can be hydroxyethyl starch. The hydroxyethylstarch can have a molecular weight of from 2 to 200 kD, preferably offrom 4 to 130 kD, more preferably of from 4 to 70 kD. Z can be analdehyde group or a keto group and the protein can be selected from thegroup consisting of IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factorVII, factor VIII, and factor IX. The aldehyde group or the keto groupcan be located in a carbohydrate side chain of the protein and/or at theN-terminal group of the protein.

The method can further comprise oxidizing the carbohydrate side chain ofthe protein and/or oxidizing the N-terminal group of the protein to givethe aldehyde group or keto group. The oxidation reaction can be carriedout enzymatically or using a periodate, in each case, if necessary,after having removed a terminal sialic acid. The method can furthercomprise reacting the polymer at its non-oxidized reducing end with anat least bifunctional linking compound comprising a functional groupcapable of reacting with the non-oxidized reducing end of the polymerand a group A, prior to the reaction of the polymer derivativecomprising A and the protein comprising Z. A can be an aminooxy group ora hydrazido group. The at least bifunctional linking compound can be ahomobifunctional compound. The homobifunctional compound can comprisetwo aminooxy groups. The homobifunctional compound can beO-[2-(2-aminooxy-ethoxy)-ethyl]hydroxyl amine. The reaction of thepolymer with the at least bifunctional linking compound can be carriedout in an aqueous medium. The reaction of the polymer with the at leastbifunctional linking compound can lead to an oxime linkage and/or anoxyamino linkage. Z can be an amino group and the protein is selectedfrom the group consisting of IFN alpha, IFN beta, GM-CSF, APC, tPA,A1AT, AT III, factor VII, factor VIII, and factor IX.

The method can further comprise selectively oxidizing the polymer at itsreducing end and reacting the oxidized polymer with N,N′-disuccinimidylcarbonate at its oxidized reducing end to give a polymer derivativecomprising the reactive carboxy group A. The method can further comprisereacting at least one hydroxy group of the polymer whose reducing end isnot oxidized, with a carbonic diester to give the reactive carboxy groupA. The carbonic diester can be a symmetrical diester. The alcoholcomponent of the ester can be selected from the group consisting ofN-hydroxy succinimide, sulfonated N-hydroxy succinimide, N-hydroxybenzotriazole, and nitro- and halogen-substituted phenols. Thehalogen-substituted phenol can be selected from the group consisting ofnitrophenol, dinitrophenol, trichlorophenol, trifluorophenol,pentachlorophenol, and pentafluorophenol. The reaction of the at leastone hydroxy group of the polymer whose reducing end is not oxidized,with the carbonic diester to give a reactive ester group A can becarried out in an anhydrous aprotic polar solvent (e.g., dimethylacetamide, dimethyl formamide or a mixture thereof).

A can be an aldehyde group, a keto group or a hemiacetal group, and themethod can further comprise reacting the polymer with a functional groupM of an at least bifunctional compound to give a polymer derivative, theat least bifunctional compound further comprising at least one otherfunctional group Q which is the aldehyde group, keto group or hemiacetalgroup A. M can comprise an amino group.

A can be an aldehyde group, keto group or hemiacetal group, and themethod can further comprise reacting the polymer with a functional groupM of an at least bifunctional compound to give a polymer derivative, theat least bifunctional compound further comprising at least one otherfunctional group Q which is not an aldehyde group, keto group orhemiacetal group, and the method further comprising reacting thefunctional group Q with at least one suitable compound to give thepolymer derivative comprising the aldehyde group, keto group orhemiacetal group A. M and Q can comprise an amino group. The at leastone suitable compound which is reacted with the functional group Q cancomprise a carboxy group and an aldehyde group, keto group or hemiacetalgroup. The at least one suitable compound which is reacted with thefunctional group Q can be formylbenzoic acid or4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid. M can comprise an aminogroup and Q can comprise a beta hydroxy amino group. The polymer can bereacted at its oxidized reducing end with a functional group M of an atleast bifunctional compound.

The method can further comprise oxidizing the beta hydroxyamino group togive the aldehyde group. The oxidation reaction can be carried out usinga periodate.

The polymer can be subjected to a ring-opening oxidation reaction usinga periodate to give a polymer derivative having at least one aldehydegroup A, in particular at least two aldehyde groups A. The reaction ofthe polymer or the polymer derivative with the protein can be areductive amination. The reductive amination can be carried out in thepresence of NaCNBH₃. The reductive amination can be carried out at a pHof 7 or less (e.g., a pH of 6 or less). The reductive amination can becarried out at a temperature of from 0 to 25° C. The reductive aminationcan be carried out in an aqueous medium.

Z can be a thiol group and the protein can be selected from the groupconsisting of IFN alpha, IFN beta, tPA, A1AT, APC, factor VII, andfactor IX. A can comprise a halogenacetyl group, and the method canfurther comprise reacting the polymer at its optionally oxidizedreducing end with an at least bifunctional compound having at least twofunctional groups each comprising an amino group to give a polymerderivative having at least one functional group comprising an aminogroup, the method further comprising reacting the polymer derivativewith a monohalogen-substituted acetic acid and/or a reactivemonohalogen-substituted acetic acid derivative. The halogen can be Br orI. The at least bifunctional compound can be a diaminoalkane having from2 to 10 carbon atoms. The at least bifunctional compound can be adiaminopolyethylene glycol having from 1 to 5 alkylene units. Thepolymer can be reacted with the at least bifunctional compound at itsoxidized reducing end. The polymer derivative comprising thehalogenacetyl group can be reacted with the protein in the presence of asolvent comprising a mixture of dimethyl formamide and water.

A can comprise a maleimido group, and the method can further comprisereacting the polymer at its optionally oxidized reducing end with an atleast bifunctional compound comprising a functional group U capable ofreacting with the optionally oxidized reducing end, the at leastbifunctional compound further comprising a functional group W capable ofbeing chemically modified to give a maleimido group, the method furthercomprising chemically modifying the functional group W to give amaleimido group. U can comprise an amino group. W can comprise an aminogroup. The polymer derivative comprising W can be reacted with an atleast bifunctional compound comprising a functional group capable ofbeing reacted with W and further comprising a maleimido group. The atleast bifunctional compound can be N-(alpha-maleimidoacetoxy)succinimideester.

In another aspect, this document features a conjugate as obtainable by amethod described herein. A can be a reactive carboxy group, and whereinA was introduced in the polymer whose reducing end was not oxidized, byreacting at least one hydroxy group of the polymer with a carbonicdiester, and wherein, the conjugate comprising one polymer molecule andat least one protein molecule, in particular of from 1 to 10 proteinmolecules linked to the polymer via amide linkages, and wherein theprotein is selected from the group consisting of IFN alpha, IFN beta,GM-CSF, APC, tPA, A1AT, AT III, factor VII, factor VIII, and factor IX.

In another aspect, this document features a conjugate comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII,factor VIII, and factor IX, the conjugate having a structure accordingto the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,wherein G is selected from the group consisting of O and S, preferablyO, and wherein L is an optionally suitably substituted, linear, branchedand/or cyclic hydrocarbon residue, optionally comprising at least oneheteroatom, preferably an alkyl, aryl, aralkyl, heteroaryl,heteroaralkyl residue having from 2 to 60 carbon atoms. -L- can be—(CH₂)_(n) with n=2, 3, 4, 5, 6, 7, 8, 9, 10, preferably 2, 3, 4, 5, 6,more preferably 2, 3, 4, and especially preferably 4.

This document also features a conjugate comprising a protein and apolymer or a derivative thereof, wherein the polymer is a hydroxyalkylstarch (HAS) and the protein is selected from the group consisting ofIFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII, factor VIII, andfactor IX, the conjugate having a structure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein G is selected from the group consisting of O and S,preferably O.

In another aspect, this document features a conjugate comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII,factor VIII, and factor IX, the conjugate having a structure accordingto the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally suitably substituted, linear, branchedand/or or cyclic hydrocarbon residue, optionally comprising at least oneheteroatom, preferably an alkyl, aryl, aralkyl, heteroaryl,heteroaralkyl residue having from 2 to 60 carbon atoms. -L- can be—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)—, wherein R_(a), R_(b),R_(c), and R_(d) are independently hydrogen, alkyl, aryl, preferablyhydrogen, wherein G is selected from the group consisting of O and S,preferably O, and wherein m is 1, 2, 3 or 4, wherein the residues R_(a)and R_(b) may be the same or different in the m groups CR_(a)R_(b); n is0 to 20, preferably 0 to 10, more preferably 1, 2, 3, 4, 5, mostpreferably 1 or 2; o is 0 to 20, preferably 0 to 10, more preferably 1,2, 3, 4, 5, most preferably 1 or 2, wherein the residues R_(c) and R_(d)may be the same or different in the o groups CR_(c)R_(d); and whereinthe integers for n and o are selected in a way that in the formulaabove, no peroxy moiety results, such as n and o are not 0 at the sametime. R_(a), R_(b), R_(c), and R_(d) can be hydrogen, m=2, n=1, and o=2.

In still another aspect, this document features a conjugate comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, the conjugate having a structureaccording to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group.

In another aspect, this document features a conjugate comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, having a structure according tothe formula

wherein the linkage —O—(C═O)— was formed by a reaction of a carboxygroup or a reactive carboxy group with a hydroxy group of the HASmolecule, and wherein HAS″ refers to the HAS molecule without thehydroxy group.

In another aspect, this document features a conjugate, comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, the conjugate having a structureaccording to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally substituted, linear, branched and/or orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom, having from 1 to 60 carbon atoms preferably from 1 to 40,more preferably from 1 to 20, more preferably from 1 to 10, morepreferably from 1 to 6 more preferably from 1 to 2 carbon atoms andespecially preferably 1 carbon atom, L being in particular CH₂.

In another aspect, this document features a conjugate, comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, the conjugate having a structureaccording to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L₁ and L₂ are independently an optionally substituted,linear, branched and/or or cyclic hydrocarbon residue, optionallycomprising at least one heteroatom, comprising an alkyl, aryl, aralkylheteroalkyl, and/or or heteroaralkyl moiety, the residue having from 1to 60 preferably from 1 to 40, more preferably from 1 to 20, morepreferably from 1 to 10 carbon atoms, and wherein D is a linkage,preferably a covalent linkage which was formed by a suitable functionalgroup F₂ linked to L₁ and a suitable functional group F₃ linked to L₂and wherein F₃ is capable of forming a chemical linkage with F₂. L₁ canbe —(CH₂)_(n)— with n=2, 3, 4, 5, 6, 7, 8, 9, 10, preferably 2, 3, 4, 5,6, more preferably 2, 3, 4, and especially preferably 4. L₂ can comprisean optionally suitably substituted aryl moiety, preferably an arylmoiety containing 6 carbon atoms, L₂ being especially preferably C₆H₄.F₂ and F₃ can be independently selected from the group consisting of

-   -   a C—C-double bond or a C—C-triple bond or an aromatic C—C-bond;    -   a thio group or a hydroxy group;    -   an alkyl sulfonic acid hydrazide, or an aryl sulfonic acid        hydrazide;    -   a 1,2-diol;    -   a 1,2 amino-thioalcohol;    -   an azide;    -   a 1,2-aminoalcohol;    -   an amino group —NH₂ or a derivative of an amino group comprising        the structure unit —NH— such as aminoalkyl groups, aminoaryl        group, aminoaralkyl groups, or alkarlyamino groups;    -   a hydroxylamino group —O—NH₂, or a derivative of a hydroxylamino        group comprising the structure unit —O—NH—, such as        hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxalalkarylamino groups;    -   an alkoxyamino group, an aryloxyamino group, an aralkyloxyamino        group, or an alkaryloxyamino group, each comprising the        structure unit —NH—O—;    -   a residue having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,    -   —OH or —SH;    -   an alkoxy group, an aryloxy group, an aralkyloxy group, or an        alkaryloxy group;    -   an alkylthio group, an arylthio group, an aralkylthio group, or        an alkarylthio group;    -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an        aralkylcarbonyloxy group, or an alkarylcarbonyloxy group;    -   an activated ester such as an ester esters of hydroxylamines        having imide imid structure such as N-hydroxysuccinimide or        having a structure unit O—N where N is part of a heteroaryl        compound or, with G=O and Q absent, such as an aryloxy compound        compounds with a substituted aryl residue such as        pentafluorophenyl, paranitrophenyl or trichlorophenyl;

wherein Q is absent or NH or a heteroatom such as S or O;

-   -   —NH—NH₂, or —NH—NH—;    -   —NO₂;    -   a nitril group;    -   a carbonyl group such as an aldehyde group or a keto group;    -   a carboxy group;    -   a —N═C═O group or a the —N═C═S group;    -   a vinyl halide group such as vinyl iodide or vinyl bromide or        triflate;    -   —C≡C—H;    -   —(C═NH₂Cl)—OAlkyl;    -   a group —(C═O)—CH2-Hal wherein Hal is Cl, Br, or I;    -   —CH═CH—SO₂—;    -   a disulfide group comprising the structure —S—S—;    -   the group

and

-   -   the group

and wherein F₃ is a functional group capable of forming a chemicallinkage with F₂ and is preferably selected from the above-mentionedgroup, F₂ preferably comprising the moiety —NH—, more preferablycomprising an amino group, F₃ preferably comprising the moiety —(C=G)-,more preferably —(C═O)—, more preferably the moiety —(C=G)-G-, stillmore preferably —(C═O)-G-, and especially preferably —(C═O)—O, D beingparticularly preferably an amide linkage.

In still another aspect, this document features a conjugate, comprisinga protein and a polymer or a derivative thereof, wherein the polymer isa hydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, the conjugate having a structureaccording to the formula

wherein the carbon atom of the moiety —CH₂—NH— is derived from analdehyde group which was introduced in the polymer by a ring-openingoxidation reaction, and wherein the nitrogen atom is derived from anamino group of the protein, wherein HAS″ refers to the HAS moleculewithout the carbon atom of the aldehyde group involved in the reaction.

This document also features a conjugate, comprising a protein and apolymer or a derivative thereof, wherein the polymer is a hydroxyalkylstarch (HAS) and the protein is selected from the group consisting ofIFN alpha, IFN beta, tPA, A1AT, factor VII and factor IX, the conjugatehaving a structure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally substituted, linear, branched and/orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom, comprising an alkyl, aryl, aralkyl heteroalkyl, and/orheteroaralkyl moiety, the residue having from 2 to 60 preferably from 2to 40, more preferably from 2 to 20, more preferably from 2 to 10 carbonatoms, and wherein the sulfur atom is derived from a cysteine residue ora disulfide group of the protein. -L- can be—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)— wherein R_(a), R_(b), R_(c)and R_(d) are independently hydrogen, alkyl, aryl, preferably hydrogen,wherein G is selected from the group consisting of 0 and S, preferablyO, and wherein

m 1, 2, 3 or 4, most preferably 2, wherein the residues Ra and Rb may bethe same or different in the m groups CR_(a)R_(b);

n 1 to 20, preferably 1 to 10, most preferably 1, 2, 3, or 4;

o 1 to 20, preferably 1 to 10, more preferably 1, 2, 3, 4, 5, morepreferably 1 or 2, most preferably 1, wherein the residues R_(c) andR_(d) may be the same or different in the o groups CR_(c)R_(d);

or wherein

n 0, and

o 2 to 20, preferably 2 to 10, more preferably 2, 3, 4, 5, 6, 7, or 8,wherein the residues Rc and Rd may be the same or different in the ogroups CR_(c)R_(d).

In another aspect, this document features a conjugate, comprising aprotein and a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, tPA, A1AT, APC, factor VII and factorIX, the conjugate having a structure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally substituted, linear, branched and/orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom, comprising an alkyl, aryl, aralkyl heteroalkyl, and/orheteroaralkyl moiety, the residue having from 2 to 60 preferably from 2to 40, more preferably from 2 to 20, more preferably from 2 to 10 carbonatoms, and wherein the sulfur atom is derived from a cysteine residue ora disulfide group of the protein. -L- can be—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)— wherein R_(a), R_(b), R_(c),and R_(d) are independently hydrogen, alkyl, aryl, preferably hydrogen,wherein G is selected from the group consisting of O and S, preferablyO, and wherein

m 1, 2, 3 or 4, most preferably 2, wherein the residues Ra and Rb may bethe same or different in the m groups CR_(a)R_(b);

n 1 to 20, preferably 1 to 10, most preferably 1, 2, 3, or 4;

o 1 to 20, preferably 1 to 10, more preferably 1, 2, 3, 4, 5, morepreferably 1 or 2, most preferably 1, wherein the residues Rc and Rd maybe the same or different in the o groups CR_(c)R_(d);

or wherein

n 0, and

o 2 to 20, preferably 2 to 10, more preferably 2, 3, 4, 5, 6, 7, or 8,wherein the residues Rc and Rd may be the same or different in the ogroups CR_(c)R_(d).

In yet another aspect, this document features a method for the treatmentof a human or animal body, comprising administering a conjugate asdescribed herein to a human or animal in need of treatment.

In another aspect, this document features a pharmaceutical compositioncomprising in a therapeutically effective amount a conjugate asdescribed herein. The pharmaceutical composition can further comprise atleast one pharmaceutically acceptable diluent, adjuvant, or carrier.

In another aspect, this document features a composition for thetreatment of leukaemia e.g. hairy cell leukaemia, chronic myelogeneousleukaemia, multiple myeloma, follicular lymphoma, cancer, e.g. carcinoidtumour, malignant melanoma and hepatitis, e.g., chronic hepatitis B andchronic hepatitis C, comprising a HAS-protein conjugate as describedherein, wherein the protein is IFN alpha.

This document also features a composition for the treatment of multiplesclerosis, preferably relapsing forms of multiple sclerosis, comprisinga HAS-protein conjugate as described herein, wherein the protein is IFNbeta.

In another aspect, this document features a composition for myeloidreconstitution following bone marrow transplant or inductionchemotherapy in older adults with acute myelogenous leukaemia, bonemarrow transplant engraftment failure or delay, mobilization andfollowing transplantation of autologous peripheral blood progenitorcells, comprising a HAS protein conjugate as described herein, whereinthe protein is GM-CSF beta.

In another aspect, this document features a composition for thetreatment of severe sepsis, thrombosis, thromboembolism or occlusivediseases, especially occlusive arterial diseases, comprising aHAS-protein conjugate as described herein, wherein the protein is APC.

In another aspect, this document features a composition for thetreatment of myocardial infarctions (heart attacks), thrombosis,thromboembolism or occlusive diseases, especially occlusive arterialdiseases, comprising a HAS-protein conjugate as described herein,wherein the protein is tPA.

In another aspect, this document features a composition for thetreatment of emphysema, cystic fibrosis, atopic dermatitis, and/or orbronchitis, comprising a HAS-protein conjugate as described herein,wherein the protein is A1AT.

In still another aspect, this document features a composition for thetreatment of hereditary deficiency, veno-occlusive disease, burns andheparin resistance in coronary arterial bypass Graft (CABG) surgery,prevention of micro-clot formation associated with ventilation therapy,treatment of bowel perforation resulting from trauma or gastrointestinalsurgery; disseminated intravascular coagulation (DIC) and/or or sepsis,comprising a HAS-protein conjugate as described herein, wherein theprotein is AT III.

In yet another aspect, this document features a composition for thetreatment of episodes in hemophilia A or B patients with inhibitors toFactor VIII or Factor IX, comprising a HAS-protein conjugate asdescribed herein, wherein the protein is factor VII.

In another aspect, this document features a composition for thetreatment of haemophilia A, comprising a HAS-protein conjugate asdescribed herein, wherein the protein is factor VIII.

This document also features a composition for the control and preventionof hemorrhagic episodes in patients with hemophillia B, preferablycongenital factor IX deficiency or Christmas disease, including controland prevention of bleeding in surgical settings, comprising aHAS-protein conjugate as described herein, wherein the protein is factorIX.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention pertains. Although methods and materialssimilar or equivalent to those described herein can be used to practicethe invention, suitable methods and materials are described below. Allpublications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Incase of conflict, the present specification, including definitions, willcontrol. In addition, the materials, methods, and examples areillustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 shows an SDS page analysis of HES-IFN beta conjugates, producedaccording to Example 1.2. A 12% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturer's instruction.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D).Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD

Lane B: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(a)

Lane C: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(b)

Lane D: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(c)

Lane E: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(d)

Lane F: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(e)

Lane G: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(f)

Lane H: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(g)

Lane I: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(h)

Lane J: Crude product after conjugation of oxidized IFN beta with HESderivative prepared as described in Example 1.1(i)

Lane K: Oxidized IFN beta, prepared as in Example 1.2(a)

FIG. 2 shows an SDS page analysis of HES-IFN beta conjugates, producedaccording to Example 1.4. A 12% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacture's instruction. Samples with avolume greater then 15 μL were concentrated in vacuo to this volume.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D)Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD.

Lane H: Conjugation of IFN-beta with aldehydo-HES synthesized asdescribed in Example 1.3(a).

Lane I: Conjugation of IFN-beta with aldehydo-HES synthesized asdescribed in Example 1.3(b).

Lane J: Control: IFN-beta, treated with sodium borohydride withoutaldehydo-HES.

FIG. 3 shows an SDS page analysis of HES-IFN alpha conjugates, producedaccording to Example 2.2. A 12% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacture's instruction. Samples with avolume greater then 15 μl were concentrated in vacuo to this volume.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D).Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD.

Lane E: Conjugation of IFN-alpha with aldehydo-HES synthesized asdescribed in Example 2.1(a).

Lane F: Conjugation of IFN-alpha with aldehydo-HES synthesized asdescribed in Example 2.1(b).

Lane G: Control: IFN-alpha according to Example 2.2, treated with sodiumborohydride without aldehydo-HES.

FIG. 4 shows an SDS page analysis of HES-AT III conjugates, producedaccording to Example 3.2. A NuPage 3-8% Tris-Acetate gel together with aTris-Acetate SDS running buffer at reducing conditions (both InvitrogenGmbH, Karlsruhe, D) were used according to the manufactures instruction.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D)Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD

Lane B: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(a)

Lane C: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(b)

Lane D: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(c)

Lane E: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(d)

Lane F: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(e)

Lane G: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(f)

Lane H: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(g)

Lane I: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 3.1(h)

Lane K: Oxidized ATIII GlycoThera, according to Example 3.2

FIG. 5 shows an SDS page analysis of HES-AT III conjugates, producedaccording to Example 3.4. A 3-8% Tris-Acetate gel together with aTris-Acetate SDS running buffer at reducing conditions (both InvitrogenGmbH, Karlsruhe, D) were used according to the manufacture'sinstruction.

Lane A: Protein marker SeeBlue®Plus2 (Invitrogen GmbH, Karlsruhe, D)Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD.

Lane B: Conjugation of AT III with aldehydo-HES synthesized as describedin Example 3.3(a).

Lane C: Conjugation of AT III with aldehydo-HES synthesized as describedin Example 3.3(b).

Lane D: Control: AT III according to Example 3.3, treated with sodiumborohydride without aldehydo-HES.

FIG. 6 shows a HPGPC (high-performance gel permeation chromatography)chromatogram with regard to the AT III purified from glycerol accordingto Example 3.5 (UV and MALLS detector results in a single chromatogram,the x axis relating to time/minutes).

The following parameters were used in the HPGPC analysis:

Column: Superose 12 HR 10/30 300×10 mm I.D. (Pharmacia)

Eluent: 27.38 mM Na₂HPO₄; 12.62 mM NaH₂PO₄; 0.2 M NaCl; 0.005% NaN₃ in 1l of demineralized water

Flux: 0.24 ml/h

Detector 1: MALLS detector

Detector 2: UV (280 nm)

Detector 3: RI (refractive index detector)

FIG. 7 shows a HPGPC chromatogram with regard to the AT III conjugateaccording to Example 3.5 (MALLS detector in the upper chromatogram, UVdetector in the lower chromatogram, the x axis relating totime/minutes).

The following parameters were used in the HPGPC analysis:

Column: Superose 12 HR 10/30 300×10 mm I.D. (Pharmacia)

Eluent: 27.38 mM Na₂HPO₄; 12.62 mM NaH₂PO₄; 0.2 M NaCl; 0.005%

NaN₃ in 1 l of demineralized water

Flux: 0.24 ml/h

Detector 1: MALLS detector

Detector 2: UV (280 nm)

Detector 3: RI (refractive index detector)

FIG. 8 shows an SDS page analysis of HES-GM-CSF conjugates, producedaccording to Example 4.2. A 12% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturer's instruction.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D)Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD

Lane B: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(a)

Lane C: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(b)

Lane D: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(c)

Lane E: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(d)

Lane F: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(e)

Lane G: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(f)

Lane H: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(g)

Lane I: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(g)

Lane J: Crude product after conjugation of oxidized GM-CSF with HESderivative prepared as described in Example 4.1(h)

Lane K: Oxidized GM-CSF according to Example 4.2.

FIG. 9 shows an SDS page analysis of HES-GM-CSF conjugates, producedaccording to Example 4.4. A 12% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacture's instruction. Samples with avolume grater then 15 μL were concentrated in vacuo to this volume.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D)Molecular weight marker from top to bottom: 188 KD, 98 KD, 62 KD, 49 KD,38 KD, 28 KD, 17 KD, 14 KD, 6 KD, 3 KD

Lane H: Conjugation of GM-CSF with aldehydo-HES synthesized as describedin Example 4.3(a)

Lane I: Conjugation of GM-CSF with aldehydo-HES synthesized as describedin Example 4.3(b)

Lane J: Control: GM-CSF according to Example 4.4, treated with sodiumborohydride without aldehydoHES

FIG. 10 shows an SDS page analysis of IFN beta-conjugates, producedaccording to Example 5.2. A 12% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacture's instruction.

Lane A: Protein marker SeeBlue® Plus2 (Invitrogen GmbH, Karlsruhe, D)Molecular weight marker from top to bottom: 188 kD, 98 kD, 62 kD, 49 kD,38 kD, 28 kD, 17 kD, 14 kD, 6 kD, 3 kD.

Lane B: Crude product after conjugation of oxidized IFN beta withhydroxylaminoHES derivative prepared as described in Example 1.1(c).

Lane C: Oxidized IFN beta.

FIG. 11 shows an SDS-PAGE gel of RP-HPLC purified HAS-modified IFN-β(CHO cell). The arrow indicates the migration position of unmodifiedIFN-β presumably due to forms lacking terminal sialic acid derivativeswhereas the HAS modified IFN-β was detected as a broad diffuse Coomassiestained area spanning molecular masses of 35 Kda-120 Kda.

FIG. 12 shows a HPAEC-PAD analysis of N-linked oligosaccharidesenzymatically released from HAS modified IFN-β

FIG. 13 shows a HPAEC-PAD analysis of N-linked oligosaccharides aftermild hydrolysis prepared from HAS modified IFN-β

FIG. 14A shows an SDS-PAGE analysis of antithrombin III: 1=untreated ATIII; 2=periodate treated AT III; 3=HAS modified AT IIII; 10 μg each wereapplied onto a 10% polyacrylamide gel

FIG. 14B shows an SDS-PAGE analysis of antithrombin III: 1=untreated ATIII; 2=periodate treated AT III; 3=HAS modified AT IIII; 10 μg each wereapplied onto a 10% polyacrylamide gel. 1+, 2+ and 3+ indicates AT IIIsamples after de-N-glycosylation with polypeptide N-glycosidase.

FIG. 15 shows a HPAEC-PAD analysis of N-linked glycans of AT III samplesobtained after polypeptide-N-glycosidase treatment as described inExample 8.6.b). 1=N-glycans from untreated AT III; 2=N-glycans from mildperiodate treated AT III; 3=N-glycans from HAS-modified AT IIII.A=elution area of neutral oligosaccharides including oligomannosidicglycans (with 6 to 9 mannose residues). B=elution area of monosialylatedN-glycans; C=elution area of disialylated N-glycans; D=elution area oftrisialylated N-glycans. The elution of HAS-modified N-glycans isindicated in trace no. 3.

FIG. 16 shows a HPAEC-PAD analysis of desialylated N-glycans (from mildacid treated Example 8.6.c)) obtained from AT III samples afterpolypeptide-N-treatment (Example 8.6.b)). 1=N-glycans from untreated ATIII; 2=N-glycans from mild periodate treated AT III; 3=N-glycans fromHAS-modified AT. In trace no. 1 the peak eluting at 16 min representsN-acetylneuraminic acid, the peak at 38 min representsN-glycolylneuraminic acid. The major meak at 19 min represent adiantennary structure with proximal a1-6-linked fucose. The remainingpeaks are diantennary without fucose, diantennry minus 1 galactose andoligomannosidic structures with mainly 6-9 mannose residues. The elutionposition of HAS-modified sialic acid derivatives is indicated in traceno. 3.

FIG. 17 shows an SDS-PAGE analysis of HAS(10 Kda)-modified GM-CSF.1=RP-HPLC eluate; 2=recombinant human GM-CSF starting material. Thebrackets indicate the migration position of C=only O-glycosylated andnon-glycosylated forms; B=GM-CSF forms with a single N-glycosylationsite occupied; A=GM-CSF with 2 N-glycosylation sites occupied withcarbohydrates (cf. Forno et al., 2004).

FIG. 18 shows an SDS-PAGE analysis of HAS(10 Kda)-modified (10 Kda)GM-CSF. 1=RP-HPLC eluate; 2=RP-HPLC eluate after digestion withpolypeptide N-glycosidase; 3=RP-HPLC eluate after mild acid treatment.The bracket indicates the GM-CSF which is presumably HAS modified atperiodate oxidised sialic acid residues attached to O-glycans.

FIG. 19 shows an HPAEC-PAD analysis of N-glycans isolated from GM-CSF.Trace 1=untreated protein; trace 2=mild periodate oxidised GM-CSF;HAS(10 Kda)-modified GM-CSF after purification by RP-HPLC. Arrows A-Eindicate the elution positions of asialo, mono-di-, tri- and tetrasialooligosaccharides. The oligosaccharide composition of the startingmaterial was essentially the same as described in reference Forno etal., 2004.

FIG. 20 shows an electrophoresis gel of the crude products afterconjugation of oxidized ATIII with HES derivatives according to example9.3. A NuPage 3-8% Tris-Acetate gel together with a Tris-Acetate SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturers instruction. The gel wasstained with Roti-Blue (Carl Roth GmbH+Co.KG, Karlsruhe, D) according tothe manufacturer's instruction.

Lane A: Protein marker Roti-Mark STANDARD (Carl Roth GmbH+Co.KG,Karlsruhe, D) Molecular weight marker from top to bottom: 200 KD, 119KD, 66 KD, 43 KD, 29 KD, 20 KD, 14.3 KD.

Lane B: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(a).

Lane C: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(b).

Lane D: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(c).

Lane E: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(d).

Lane F: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(e).

Lane G: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(f).

Lane H: Crude product after conjugation of oxidized ATIII with HESderivative prepared as described in Example 9.1(g).

Lane K: Reaction control.

FIG. 21 shows an electrophoresis gel of ATIII conjugates producedaccording to example 9.4. A NuPage 3-8% Tris-Acetate gel together with aTris-Acetate SDS running buffer at reducing conditions (both InvitrogenGmbH, Karlsruhe, D) were used according to the manufacturer'sinstruction. The gel was stained with Roti-Blue (Carl Roth GmbH+Co.KG,Karlsruhe, D) according to the manufacturer's instruction.

Lane A: Protein marker Roti-Mark STANDARD (Carl Roth GmbH+Co.KG,Karlsruhe, D) Molecular weight marker from top to bottom: 200 KD, 119KD, 66 KD, 43 KD, 29 KD, 20 KD, 14.3 KD.

Lane B: Crude product after conjugation of ATIII with HES derivativeprepared as described in Example 9.2(b).

Lane C: Crude product after conjugation of ATIII with HES derivativeprepared as described in Example 9.2(d).

Lane D: Reaction control.

Lane E: Protein marker Roti-Mark STANDARD.

FIG. 22 shows SEC of IFN-alpha-HES coupled via activated aldonic acidsaccording to example 10.3. MALLS and UV-detection proved the high degreeof conversion of IFN-alpha in the reaction.

FIG. 23 is a graph showing the activity of Intron® A compared to NIHstandard IFN-alpha 2a (see example 11.1)

FIG. 24 is a graph showing the relative in vitro activity ofIFN-alpha-HES (right column) compared to Intron® A (left column), seeexample 11.2.

FIG. 25 is a graph showing the result of example 12.2 (the trianglerepresents IFN-alpha starting material, the squares representHES-modified IFN alpha; dilution of serum samples required to achieve a50% protection of MDBK cells against viral infection vs. time post i.v.injection of 30 μg/kg in mice). Serum from mice treated with unmodifiedstarting material has a very low antiviral effect. Modification ofIFN-alpha with HES substantially prolongs the antiviral effect of serum.

FIG. 26 shows results of example 13 (analysis of the crude α1AT-HESconjugates prepared as described in example 13.5 by gelelectrophoresis). A 3-8% Tris-Acetate gel together with a Tris-AcetateSDS running buffer at reducing conditions (both Invitrogen GmbH,Karlsruhe, D) were used according to the manufacturer's instruction.

Lane A: Unstained SDS Page Protein Marker 6.5-200 KDa (SERVAElektrophoresis GmbH, Heidelberg, D) Molecular weight marker from top tobottom: 200 KD, 116 KD, 67 KD, 45 KD, 29 KD, 21 KD, 14.3 KD, 6.5 KD;

Lane B: Conjugation to aldehydo-HES as described in example 13.5;

Lane C: Conjugation to HES as described in example 13.6.

FIG. 27 shows results of example 13 (analysis of the fractions B1-C6collected after Ion Exchange Chromatography (see example 13.7)

Lane A: Unstained SDS Page Protein Marker 6.5-200 KDa (SERVAElektrophoresis GmbH, Heidelberg, D) Molecular weight marker from top tobottom: 200 KD, 116 KD, 67 KD, 45 KD, 29 KD, 21 KD, 14.3 KD, 6.5 KD;

Lane B: Fraction B1

Lane C: Fraction C1

Lane D: Fraction C2

Lane E: Fraction C3

Lane F: Fraction C4

Lane G: Fraction C5

Lane H: Fraction C6

Lane I: A1AT (GTC Biotherapeutics Inc., Framingham, Mass., lot No.080604A)

FIG. 28 is a graph showing the residual enzyme activity vs.concentration plot of Prolastin® HS (Bayer Vital GmbH, Leverkusen,Germany, Lot No. PR4HA43), A1AT (GTC Biotherapeutics Inc., Framingham,Mass., lot No. 080604A) and a HES-A1AT-conjugate synthesized asdescribed in example 13.5

FIG. 29 shows the analysis of IFN-alpha-HES conjugates of example 14.3.1by gel electrophoresis. A 10% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturer's instruction.

Lane X: Roti®-Mark STANDARD (Carl Roth GmbH+Co. KG, Karlsruhe, D)Molecular weight marker from top to bottom: 200 KD, 119 KD, 88 KD, 43KD, 29 KD, 20 KD, 14.3 KD;

Lane A: Conjugation to aldehydoHES 10/0.4 as described in ex. 14.3.1,entry A;

Lane B: Conjugation to aldehydoHES 10/0.7 as described in ex. 14.3.1,entry B;

Lane C: Conjugation to aldehydoHES 30/0.4 as described in ex. 14.3.1,entry C;

Lane D: Conjugation to aldehydoHES 30/0.7 as described in ex. 14.3.1,entry D;

Lane E: Conjugation to aldehydoHES 50/0.4 as described in ex. 14.3.1,entry E;

Lane F: Conjugation to aldehydoHES 50/0.7 as described in ex. 14.3.1,entry F;

Lane G: Reaction control, without aldehydoHES as described in ex.14.3.1, entry G;

Lane I: Reaction control, without aldehydoHES and without NaCNBH3 asdescribed in ex. 14.3.1, entry I;

Lane J: Reaction control, with HES10/0.4 as described in ex. 14.3.1,entry J;

Lane K: Reaction control, with HES10/0.4 but without NaCNBH3 asdescribed in ex.

14.3.1, entry K.

FIG. 30 shows an analysis of IFN-alpha-HES conjugates of example 14.3.2by gel electrophoresis. A 10% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturer's instruction.

Lane X: Roti®-Mark STANDARD (Carl Roth GmbH+Co. KG, Karlsruhe, D)Molecular weight marker from top to bottom: 200 KD, 119 KD, 88 KD, 43KD, 29 KD, 20 KD, 14.3 KD;

Lane A: Conjugation to aldehydo-HES as described in example 14.3.2 entryA;

Lane B: Conjugation to aldehydo-HES as described in example 14.3.2 entryB;

Lane C: Conjugation to aldehydo-HES as described in example 14.3.2 entryC;

Lane D: Conjugation to aldehydo-HES as described in example 14.3.2 entryD;

Lane E: Conjugation to aldehydo-HES as described in example 14.3.2 entryE;

Lane F: Conjugation to aldehydo-HES as described in example 14.3.2 entryF;

Lane G: Reaction control, with HES as described in example 14.3.2 entryG.

No reaction was observed for the reaction control G.

FIG. 31 shows an analysis of IFN-alpha-HES conjugates of example 14.3.3by gel electrophoresis. A 10% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturer's instruction.

Lane A: Roti®-Mark STANDARD (Carl Roth GmbH+Co. KG, Karlsruhe, D)Molecular weight marker from top to bottom: 200 KD, 119 KD, 66 KD, 43KD, 29 KD, 20 KD, 14.3 KD;

Lane B: Conjugation of IFNα to AldehydoHES 30/0.8 as described in14.3.3;

Lane C: Conjugation of IFNα to AldehydoHES 130/0.7 as described in14.3.3;

Lane D: Conjugation of IFNα to HES 10/0.4 sodium (Reaction Control) asdescribed in 14.3.3

FIG. 32 shows an analysis of IFN-alpha-HES conjugates of example 14.3.4by gel electrophoresis. A 10% Bis-Tris gel together with a MOPS SDSrunning buffer at reducing conditions (both Invitrogen GmbH, Karlsruhe,D) were used according to the manufacturer's instruction.

Lane X: Roti®-Mark STANDARD (Carl Roth GmbH+Co. KG, Karlsruhe, D)Molecular weight marker from top to bottom: 200 KD, 119 KD, 88 KD, 43KD, 29 KD, 20 KD, 14.3 KD

Lane A: Conjugation to aldehydo-HES as described in example 14.3.4;

Lane B: Reaction control; conjugation to HES as described in example14.3.4.

No reaction was observed for the reaction control B.

FIG. 33 is a graph showing the proliferative activity of Intron® Acompared to NIH standard rhIFN-alpha 2a according to example 15.1.

FIG. 34 is a graph showing the relative in vitro activity of mockincubated IFN-alpha-HES compared to unmodified IFN-alpha startingmaterial according to example 15.2.

FIG. 35 is a graph showing relative in vitro activity of IFN-alpha-HESconjugates compared to unmodified IFN-alpha starting material, Intron® Aand Pegasys, respectively, according to example 15.3.

FIG. 36 is a graph showing the relative in vitro activity ofIFN-alpha-HES conjugate compared to Intron® A according to example 15.4.

FIG. 37 is a graph showing the results of example 15.5 in a graph(antiviral activity of IFN-alpha-HES conjugates)

FIG. 38 is a graph showing the dilution of serum samples required toachieve a 50% protection of MDBK cells against viral infection vs. timepost i.v. injection of 30 g/kg in mice. Serum from mice treated withunmodified starting material has a very low antiviral effect.Modification of IFN-alpha with HES prolongs the antiviral effect ofserum substantially. The half life increases with molecular weight ofHES used for modification of IFN-alpha (see example 16).

FIG. 39 is a graph showing the results of example 16.3 in a graph(antiviral activity of IFN-alpha-HES conjugates)

FIG. 40 is a graph showing data from the PK-Study in rabbits accordingto example 17. IFN-alpha-HES shows a distinct prolongation of half-lifecompared to the IFN-alpha starting material. For >24 h (approx. <1000pCi/m1) the curve of the unmodified material levels off and almost nofurther decrease of activity can be observed

FIG. 41 is a graph showing PK-Study in rabbits according to example 17.Data were evaluated in the period between 4 and 24 h. IFN-alpha-HESshows a distinct prolongation of half-life compared to the unmodifiedIFN-alpha starting material.

FIG. 42 is a graph showing the statistical evaluation of the PK-Study(shown: period up to 12 h) according to example 17. In the case of theunmodified starting material (see FIG. 42( a)), the concentrationdropped to almost zero during the first two hours, whereas IFNalpha-HESshows a distinctly prolonged half-life (FIG. 42( b)).

FIG. 43 shows an SDS-PAGE analysis of the crude alpha1AT-HES conjugateprepared as described in example 18.5. A 3-8% Tris-Acetate gel togetherwith a Tris-Acetate SDS running buffer at reducing conditions (bothInvitrogen GmbH, Karlsruhe, D) were used according to the manufacturesinstruction.

Lane A: Unstained SDS Page Protein Marker 6.5-200 KDa (SERVAElektrophoresis GmbH, Heidelberg, D) Molecular weight marker from top tobottom: 200 KD, 116 KD, 67 KD, 45 KD, 29 KD, 21 KD, 14.3 KD, 6.5 KD;

Lane B: alpha1AT (GTC Biotherapeutics Inc., Framingham, Mass., lot No.080604A);

Lane C: Conjugation to MaleimidoHES as described in example 18.5;

Lane D: Conjugation to MaleimidoHES as described in example 18.5 (doubleconcentration);

FIG. 44 shows an analysis of the fractions A, B, and C collected afterIon exchange chromatography (see example 18.7). A 3-8% Tris-Acetate geltogether with a Tris-Acetate SDS running buffer at reducing conditions(both Invitrogen GmbH, Karlsruhe, D) were used according to themanufacturer's instruction.

Lane 1: Unstained SDS Page Protein Marker Mark12® 2.5-200 KDa(Invitrogen GmbH, Karlsruhe, D) Molecular weight marker from top tobottom: 200 KD, 116 KD, 97 KD, 66 KD, 55 KD, 36 KD, 31 KD, 21 KD; 14 KD,4KD

Lane 2: Fraction A

Lane 3: Fraction B

Lane 4: Fraction C

Lane 5: alpha1AT (GTC Biotherapeutics Inc., Framingham, Mass., lot No.080604A).

DETAILED DESCRIPTION

The proteins which can be conjugated according to the invention can becharacterized as follows:

Interferons are cytokines that mediate antiviral, anti-proliferative andimmuno-modulatory activities in response to viral infection and otherbiological inducers. In contrast to IFN alpha, IFN beta is highlyspecies-specific. There are two subtypes of IFN beta, IFN beta 1a andIFN beta 1b. When it comes to industrial production then the maindifference between IFN beta 1a and IFN beta 1b is the respective cellsystems utilized for their production with consequences forglycosylation and number of amino acids. IFN beta 1a is produced bymammalian cells and receives the designation 1a because its amino acidsequence is identical to that of the naturally occurring interferonbeta. IFN beta 1b is produced by bacteria. Interferons, like most othermammalian proteins are modified post-translationally by glycosylation.Bacteria, however, lack the ability to glycosylate proteins and thus IFNbeta 1b does not include the carbohydrate side chains found in thenatural material. IFN beta 1a has 166 amino acids and a molecular weightof about 22,500 D, IFN beta 1b has 165 amino acids and a molecularweight of about 18,500 D, because the N-terminal methionin is missing inIFN beta 1b as well as the glycosylation due to the bacterial productionmethod. The amino acid sequence of human interferon beta is given, e.g.,in EP 0 218 825 A1. The crystal structure of interferon beta wasreported in: Proc. Natl. Acad. Sci. USA 94 (1997) pp 11813-11818,Biochemistry, Karpusas M, Nolte M, Benton C B, Meier W, Lipscomb W N,Goelz S. Commercial preparations of interferon beta are Betaseron (IFNbeta 1b), Avonex and Rebif (IFN beta 1a). Interferon beta 1b ismanufactured by bacterial fermentation of a strain of E. coli that bearsa genetically engineered plasmid containing the gene for humaninterferon beta_(ser17). The native gene was obtained from humanfibroblasts and altered in a way that substitutes serine for thecysteine residue found at position 17. Interferon beta 1a is produced byrecombinant DNA technology using genetically engineered Chinese HamsterOvary (CHO) cells into which the human interferon beta gene has beenintroduced. The amino acid sequence of IFN beta 1a is identical to thatof natural fibroblast derived human interferon beta. Natural interferonbeta and interferon beta 1a are glycosylated with each containing asingle N-linked complex carbohydrate moiety at the Asn80. The interferonbeta drugs are indicated for the treatment of relapsing remittingmultiple sclerosis. However, there are many serious side effects relatedto the administration of the interferon beta drug products. Furthermorethey are administered by injection (intramuscular or subcutanously),leading to additional risks. Reducing the side effects and easier (e.g.less frequent) administration are the reason, why lot of developmentwork is performed to improve the properties of IFN beta. Polymermodification of proteins is a technique which is applied to improve theproperties of the proteins. The mainly used technique is themodification of interferon with polyethylen glycol, known as PEGylation.

IFN alpha forms are naturally produced by monocytes/macrophages,lymphoblastoid cells, fibroblasts and a number of different cell typesfollowing induction by viruses, nucleic acids, glucocorticoid hormones,and other inductors. At least 23 different variants of IFN alpha areknown. The individual proteins have molecular masses between 19-26 kDand consist of proteins with lengths of 156-166 or 172 amino acids. AllIFN alpha subtypes possess a common conserved sequence region betweenamino acid positions 115-151 while the amino-terminal ends are variable.Many IFN alpha subtypes differ in their sequences only at one or twopositions. Disulfide bonds are formed between cysteins at positions 1/98and 29/138. The disulfide bond 29/138 is essential for biologicalactivity while the 1/98 bond can be reduced without affecting biologicalactivity. All IFN alpha forms contain a potential glycosylation site butmost subtypes are not glycosylated. In contrast to IFN gamma, IFN alphaproteins are stable at a pH of 2. Industrial production of IFN alpha isperformed using genetically modified E. coli. Because bacteria lack theability to glycosylate proteins, the two variants of IFN alpha (IFNalpha 2a, and IFN alpha 2b), which are used in approved drug products,are both non-glycosylated. A major drawback of conventional IFN alphaare the side effects. A lot of work has been done on improvement ofinterferon alpha drugs, which are indicated for treatment of HepatitisC. Polymer modification of proteins is a technique which is applied toimprove the properties of the proteins. The mainly used technique is themodification of interferon with polyethylen glycol, known as PEGylation.Two commercially available PEGylated variants of IFN-alpha are PEGIntron(SP) and Pegasys (Roche).

Antithrombin III (AT III) is a serine protease inhibitor that inhibitsthrombin and factor Xa (Travis, Annu. Rev. Biochem. 52: 655, 1983). To alesser extent, factor IXa, XIa, XIIa, tPA, urokinase, trypsin, plasminand kallikrein are also inhibited (Menache, Semin. Hematol. 28:1, 1991;Menache, Transfusion 32:580, 1992; Lahiri, Arch. Biochem. Biophys.175:737, 1976). Human AT III is synthesized in the liver as a singlechain glycoprotein of 432 amino acids with a molecular weight (MW) ofapproximately 58.000 D. Its normal plasma concentration is within therange of 14-20 mg/dL (Rosenberg, Rev. Hematol. 2:351, 1986; Murano,Thromb. Res. 18:259, 1980). The protein bears three disulfide bridges(Cys 8-128, Cys 21-95, Cys 247-430) and four N-linked carbohydratechains (Asn 96, -135, -155, -192) which account for 15% of the totalmass (Franzen, J. Biol. Chem. 255:5090, 1980; Peterson, ThePhysiological Inhibitions of Blood Coagulation and Fibrinolysis,Elsevier/North-Holland Biomedical Press 1979, p 43). Antithrombin is aserine proteinase inhibitor of the serpin type that is of majorimportance in the control of blood coagulation. AT III is the mostabundant endogenous anticoagulant circulating in human plasma andparticipates in the regulation of clotting in both physiologic andpathologic states (Opal, Crit. Care Med. 2002, 30:325). It circulates intwo forms with low thrombin inhibitory capacity (Pike, J. Biol. Chem.272:19562, 1997; Ersdal-Badju, Fed. Proc. 44:404, 1985) (85-95% alphaisoform with 4 biantennary, mono- and di-sialylated oligosaccharidechains, 5-15% is the high heparin affinity beta isoform lackingglycosylation at Asn 135, 2-6 terminal sialic acid linkage). A smallfraction of the circulating AT III is normally bound to proteoglycans onthe surface of vascular endothelial cells. These proteoglycans arepredominantly heparan sulfate, a molecule structurally similar toheparin, which is able to catalyze the inhibition of thrombin in thesame way as heparin. The AT III binding to well defined pentasaccharideunits of heparin causes a conformational change of the protein (Choay,Ann. NY Acad. Sci. 370:644, 1981; Choay, Biochem. Biophys. Res. Commun.116:492, 1983; Olson, J. Biol. Chem. 266:6353, 1991; Bauer, Semin.Hematol. 28:10, 1991; Carell, Thromb. Haemost. 78:516, 1997). Thisbinding catalyzes a 1000 fold increase of AT III inhibitory activitytoward thrombin and Factor Xa (Rosenberg, Fed. Proc. 44:404, 1985;Bjork, “Antithrombin and related inhibitors of coagulation proteinases,”in Barett, Salvesen (eds.): Proteinase Inhibitors, vol 17, Amsterdam,The Netherlands Elsevier Science Publishers (Biomedical Devision) 1986 p489; Olson, J. Biol. Chem. 267:12528, 1992). This localization of afraction of the AT on the endothelial surface, where enzymes of theintrinsic coagulation cascade are commonly generated, enables AT III torapidly neutralize these hemostatic enzymes and protect natural surfacesagainst thrombus formation. Thus, the key properties of AT III inprevention of thrombotic events are its ability to bind the catalystheparin, undergo the conformational change that alters its inhibitoryproperties, and irreversibly bind thrombin or Factor Xa therebyinhibiting their activities. AT III also has anti-inflammatoryproperties, several of which result from its actions in the coagulationcascade (Roemisch, Blood Coagul Fibrinolysis. 2002, 13:657). Activatedcoagulation proteases like activated factor X and thrombin contribute toinflammation, for instance by the release of pro-inflammatory mediators.Inhibition of these proteases by AT III prevents their specificinteraction with cells and subsequent reactions (Roemisch, Blood CoagulFibrinolysis. 2002, 13:657). Anti-inflammatory properties of AT IIIindependent of coagulation involve direct interactions with cellsleading to the release of, for instance, prostacyclin. Binding of AT IIIto a recently identified cellular receptor, syndecan-4, leads to theinterference with the intracellular signal induced by mediators likelipopolysaccharides and, thereby, to a down-modulation of theinflammatory response (Roemisch, Blood Coagul Fibrinolysis. 2002,13:657). Beside the analysis of the free AT III structure, many studieshave been conducted evaluating the complexation sites foroligosaccharide units of heparin due to the importance of the heparin-ATIII complex for the physiological function of AT III (Choay, Ann. NYAcad. Sci. 370:644, 1981; Choay, Biochem. Biophys. Res. Commun. 116:492,1983; Olson, J. Biol. Chem. 266:6353, 1991; Bauer, Semin. Hematol.28:10, 1991; Carell, Thromb. Haemost. 78:516, 1997). AT III can beproduced following classical human plasma fractionating techniques.Affinity chromatography (heparin-sepharose) using the high affinity ofheparin for AT III followed by heat treatment for virus inactivation isused for the separation from plasma. More recent alternatives areavailable for the AT III production are recombinant productiontechniques that provide a safer access to this therapeutic Protein(Levi, Semin Thromb Hemost 27: 405, 2001). ATryn™ is a recombinant humanAT III (rh AT III) produced by Genzyme Transgenics Corp. (GTC) intransgenic goats. Detailed investigations have been conducted comparingthe structural and functional properties of both plasma derived AT III(ph AT III) and rh AT III (Edmunds, Blood, 91:4561, 1998). Based on thisexperiments rh AT III is structurally identical to ph AT III with theexception of the glycosylation. Oligomannose structures were found onAsn 155 of the transgenically produced material whereas complexstructures are detected in the case of the plasma derived protein. Someof the galactose units of the pd AT III are substituted by GalNac unitsin the rh AT III. A higher degree of fucosylation in rh AT III isanother difference. Finally the sialylation pattern of both proteinsdiffers in two ways: The rh AT III is less sialylated and containsN-acetyl- as well as N-glycolylneuramin acids. This structuraldifference between the two carbohydrate parts of both molecules alsoresults in different biochemical properties. The following AT III drugsare available on the European hospital market. (Source: IMS-ATC group2001): Kybernin (Aventis Behring), AT III (Baxter, Grifols), Atenativ(Pharmacia), Aclotine (LFB), Grifols (Anbin).

Factor VII participates in the intrinsic blood coagulation cascade ofproteinases and promoting hemostatsis by activating the extrinsicpathway of the coagulation cascade. F VII is converted to factor VIIa byfactor Xa, factor XIIa, factor IXa, or thrombin by minor proteolysis. Inthe presence of tissue factor and calcium ions, factor VIIa thenconverts factor X to factor Xa by limited proteolysis. Factor VIIa willalso convert factor IX to factor IXa in the presence of tissue factorand calcium. Factor VII is a vitamin K-dependent glycoprotein consistingof 406 amino acid residues (MW 50 K Dalton). Factor VII is eitherproduced by conventional extraction from donated human plasma or, morerecently, using recombinant systems. Novo Nordisk uses Baby hamsterkidney (BHK) cells for production of NovoSeven®. Expressed as thesingle-chain protein of 406 amino acids with a nominal molecular weightof 55 kDa (Thim, L. et al., Biochemistry 27:7785-7793(1988). Themolecule bears four carbohydrate side chains. Two O-linked carbohydrateside chains at Ser 52, 60 and two N-linked carbohydrate side chains atAsn 145, 322 (Thim, L. et al., Biochemistry 27:7785-7793(1988).

Factor VIII participates in the intrinsic blood coagulation cascade ofproteinases and serves as a cofactor in the reaction of factor IXaconverting factor X to the active form, factor Xa, which ultimatelyleads to the formation of a fibrin clot. A lack or instability of factorVIII leads to haemophilia A, a common recessive x-linked coagulationdisorder. The frequency of haemophilia A is 1-2 in 10,000 male births inall ethnic groups. Patients either do express levels of factor VIII wellbelow normal or belong to the so-called group of crm (cross-reactingmaterial) positive patients (approximately 5% of patients) that haveconsiderable amount of factor VIII in their plasma (at least 30% ofnormal), but the protein is non-functional. About 50% of all patientshave severe haemophilia a with a factor VIII activity of less than 1% ofnormal; they have frequent spontaneous bleeding into joints, muscles andinternal organs.

Mild haemophilia A, which occurs in 30-40% of patients, is associatedwith an activity of 5-30% of normal. Bleeding occurs only aftersignificant trauma or surgery. Moderately severe haemophilia a occurs inabout 10% of patients; Here, factor VIII activity is 2-5% of normal, andbleeding occurs already after minor trauma.

The human in-vivo half-life of factor VIII is usually 10-15 hours but ithas to be noted that the release, stability, and degradation kineticsare also influenced by another factor, the van Willebrand factor.

Factor VIII is either produced by conventional extraction from donatedhuman plasma or, more recently, using recombinant systems. Bayer usesBaby hamster kidney (BHK) cells for production of Kogenate, whereasBaxter uses Chinese Hamster Ovary (CHO) cells for its productRecombinate. as the full single-chain protein of 2351 amino acids with anominal molecular weight of 267 kDa (Toole et al., 1984, Nature 312:342) or in different versions, where the full B-domain or parts of itare deleted in order to have a product that is more stable and gives ahigher yield in production (Bhattacharyya et al. 2003, CRIPS 4/3: 2-8).The precursor product is processed into two polypeptide chains of 200and 80 kDa in the Golghi and the two chains which are held together bymetal ion(s) are expressed in the blood (Kaufman et al., 1988, J. Biol.Chem., 263: 6352).

Procoagulant activity requires further thrombin cleavage to yield 54 kDaand 44 kDa fragments of the heavy chain plus a 72 kDa light-chainfragment (Aly et al., 1992, Proc. Natl. Acad. Sci. USA: 4933). In factorVIII concentrates derived from human plasma several fragmented fullyactive factor VIII forms have thus been described (Anderson et al.,1986, Proc. Natl. Acad, Sci. 83: 2979).

A common side effect of the administration of plasmatic or recombinantfactor VIII are immunological reactions in quite a high number ofpatients (up to 30%), that forfeit the therapeutic value. In the past,various attempts to tolerate the patients by oral induction of tolerancewere started but results were not all too encouraging. New genetic meansof inducing tolerance have been proposed but not yet found widespreadapplication. A hesylated protein is expected to have a lower degree ofimmunogenicity and could thus reduce this complication.

Factor VIII is very rich in lysine residues (over 220 of the overall2350 amino acids; see attachment 1), that could be used for theReductive Amination approach.

Factor IX is a vitamin K-dependent plasma protein that participates inthe intrinsic pathway of blood coagulation by converting factor X to itsactive form in the presence of Ca(2+) ions, phospholipids, and factorVIIIa. Factor IX is a glycoprotein with an approximate molecular mass of55,000 Da consisting of 415 amino acids in a single chain (Yoshitake S.et al., Biochemistry 24:3736-3750(1985)). Factor IX is either producedby conventional extraction from donated human plasma or, more recently,using recombinant systems. Wyeth uses Chinese hamster ovary (CHO) cellsfor production of BeneFIX®. It has a primary amino acid sequence that isidentical to the Ala¹⁴⁸ allelic form of plasma-derived factor IX, andhas structural and functional characteristics similar to those ofendogenous factor IX. The protein bears eight carbohydrate side chains.Six O-linked carbohydrate side chains at Ser 53, 61 and at Threonine159, 169, 172, 179 and two N-linked carbohydrate side chains at Asn 157,167 (Yoshitake S. et al., Biochemistry 24:3736-3750(1985); Balland A. etal., Eur J Biochem. 1988; 172(3):565-72).

Human granulocyte macrophage colony stimulating factor (hGM-CSF) is anearly acting factor essential for regulation and differentiation ofhaematopoietic progenitor cells as well as for stimulating functionalactivation of mature cell populations. It has been cloned and expressedin yeast, bacteria, insect, plant and mammalian cells, resulting in aprotein that varies in structure, composition, serum half-life andfunctions in vivo (Donahue, R. E. et al. Cold Spring Harbor Symp. Quant.Biol. 1986, 51: 685-692). Natural and mammalian cell-derived hGM-CSF isa 127 amino acid protein and it contains both N- and O-glycans. It ishighly heterogeneous due to the different states of occupancy of one ortwo N-glycosylation sites and the O-glycosylation site(s) (Cebon, J. etal. J. Biol. Chem. 1990, 265: 4483-4491; Kaushansky, K. et al.Biochemistry 1987, 26: 4861-4867; Armitage, J. O. Blood 1998, 92:4491-4508). This lymphokine is of clinical interest due to its potentialthe treatment of myeloid leukemia and its ability to stimulate thegranulocyte and macrophage production in patients sufferingimmunodeficiency or being suppressed by disease or radiation and/orchemotherapy (reviewed by Moonen, P. et al. Proc. Natl. Acad. Sci. USA.1987, 84: 4428-4431). Several studies have suggested that hGM-CSFlacking N-linked carbohydrate has a significantly higher specificactivity in vitro when compared to the native recombinant cytokine(Armitage, J. O. Blood 1998, 92: 4491-4508; Okamoto, M. et al. Arch.Biochem. Biophys. 1991, 286: 562-568; Hovgaard, D. et al. Eur. J. Clin.Inv. 1992, 22: 45-49). However, there are numerous evidences supportingthe key role of carbohydrate chains in hGM-CSF functions, such aspharmacokinetic (Cebon, J. et al. J. Biol. Chem. 1990, 265: 4483-4491;Hovgaard, D.; et al. Eur. J. Clin. Inv. 1992, 22: 45-49; Denzlinger, C.et al. Blood 1993, 81: 2007-2013), toxicity (Denzlinger, C. et al. Blood1993, 81:2007-2013) and immunogenicity (Donahue, R. E. et al. ColdSpring Harbor Symp. Quant. Biol. 1986, 51: 685-692; Revoltella, R. etal. Leukemia and Lymphoma 1997, 26: 29-34; Ragnhammar, P. et al. Blood1994, 84:4078-4087; Wadhwa, M. et al. Clinical Cancer Research 1999,5:1351-1361; Gribben, J. G. et al. Lancet 1990, 335: 434-437). In viewof the antigenecity which has been frequently reported for GM-CSFclinical products from E. coli and from yeast, the chemical modificationstrategy is suggested to represent a promising approach for this productincluding those manufactured from non-mammalian expression systems.GM-CSF preparations are available under the names Leukine (Immunex) andLeucomax (Novartis). GM-CSF is used in myeloid reconstitution followingbone marrow transplant, bone marrow transplant engraftment failure ordelay, mobilization and following transplantation of autologousperipheral blood progenitor cells, and following induction chemotherapyin older adults with acute myelogenous leukemia.

Alpha1-Antitrypsin (A1AT, also referred to as alphal-proteinaseinhibitor) is a proteinase inhibitor that has been shown to inhibitvirtually all mammalian serine proteinases (Travis Ann. Rev. Biochem. 52(1983) p. 655) including neutrophil elastase, thrombin, factors Xa andXIa. A1AT is a single chain glycoprotein synthesized in the liver with394 amino acids and a molecular weight of 53 kD. The plasmaconcentration is within a range of 1-1.3 g/l. The presence of only onecysteine in the whole protein does not allow the formation ofintramolecular disulfide bridges. The molecule bears three carbohydrateside chains (Asn 46, 83, 247) (Mega J. Biol. Chem. 255 (1980) p. 4057;Mega J. Biol. Chem. 255 (1980) p. 4053; Caren FEBS Letters 135 (1981) p.301; Hodges Biochemistry 21 (1982) p. 2805) that represent 12% of themolecular weight. Two types of carbohydrate chains were discoveredhaving a bi- or triantennary structure, respectively (Hodges J. Biol.Chem. 254 (1979) p. 8208). Human A1AT occurs in at least twentydifferent forms in the general population. This micro-heterogenicity isa result of variable amounts of the two types of carbohydrate chains.The key function is the activity control of neutrophil elastase (TravisAnn. Rev. Biochem. 52 (1983) p. 655). An uncontrolled activity ofelastase leads to an attack on epithelial tissues with the result ofirreparable damage. During the inactivation process A1AT acts as asubstrate for elastase binding to the active center of the protease wichis subsequently inactivated by this complex formation. A deficiency ofA1AT causes e.g. pulmonary emphysema which is in connected with a damageof the pulmonary epithelium. The distribution of the two types ofcarbohydrate side chains of A1AT to the three N-glycosylation sites ofA1AT is different for each isotype of A1AT. The classical production ofA1AT is conducted in human plasma fractionation using differentaffinity-chromatography steps. However a more recent way of producingA1AT is the use of recombinant techniques. PPL Therapeutics hasdeveloped a process that allows to recover recombinant human A1AT(rHA1AT) from the milk of transgenic sheep (Olman Biochem. Soc. Symp. 63(1998) p. 141; Tebbutt Curr. Opin. Mol. Ther. 2 (2000) p. 199; CarverCytotechnology 9 (1992) p. 77; Wright Biotechnology (NY) 9 (1991) p.830). With respect to the protein part of the molecule the rhA1AT showsan identical structure compared to pdA1AT. But—as is the case for otherrecombinant produced human proteins—differences occur in thecarbohydrate side chains, especially with regard to the amount of sialicacid residues.

The tissue type plasminogen activator (tPA) is a trypsine like serineprotease important in clot lysis. In the presence of a fibrin clot, tPAconverts plasminogen to plasmin, which degrades fibrin. TPA exhibitsenhanced activity in the presence of fibrin and as a result, causesfibrin-specific plasminogen activation (M. W. Spellman, L. J. Basa, C.K. Leonard, J. A. Chakel, J. V. O'Connor, J. Biol. Chem. 264 (1989) p.14100). Plasmin solubilizes fibrin, yielding fibrin degradationproducts. Through a positive feedback mechanism, fibrin enhances its owndegradation by stimulating tPA mediated plasminogen activation (R. J.Stewart et. al. J. Biol. Chem. 275 (2000) pp. 10112-10120). htPA is aphysiological activator of fibrinolysis, which is present in differenttypes of tissues. It is a glycoprotein with a molecular weight ofapprox. 68 kD. In native form tPA exists in a one-chain-form(single-chain tissue-type plasminogen activator, sctPA), which can beconverted by cleavage of plasmin at the peptide bond Arg 275-Ile 276 toa two chain structure (two-chain tissue-type plasminogen activator,tctPA). For therapy of fibrinolysis it is produced recombinant as rtPA(recombinant tissue-type plasminogen activator). Different types of tPAexist showing structural differences in the carbohydrate structure. TypeI tPA has N-linked oligosaccharides at amino acids Asn117, Asn184 andAsn448. Type II tPA is glycosylated at Asn117 and Asn448. Both typescontain an O-linked fucose residue at Thr61 (K. Mori et. al. J. Biol.Chem. 270 (1995) pp. 3261-3267). The carbohydrate structure of tPAexpressed in CHO-cells was investigated, showing a large variety of di-,tri- and tetraantennary structures of the sugar chains (M. W. Spellman,L. J. Basa, C. K. Leonard, J. A. Chakel, J. V. O'Connor, J. Biol. Chem.264 (1989) p. 14100). The primary structure of tPA contains severalcysteines, that are believed to be cross-linked plus a free cysteineresidue at site 83, which may interact with another tPA, forming adimer. Several results indicate that the in-vivo clearance of tPA isinfluenced by the carbohydrate structure, particularly by the highmannose oligosaccharide attached at site Asn117. Another proposedclearance mechanism involves the recognition of the O-linked fucoseresidue at Thr61 by a high affinity receptor on hepatocytes. Thisresidue is close to Cys83. A bioengineered tPA (TNK-tPA) was developedto prolong the half-life. The glycosylation site at position 117 wasshifted to position 103 by substituting Asparagine at site 117 withGlutamine and Threonine at site 103 substituted with Asparagine. TNK-tPAis resistant to inactivation by plasminogen activator inhibitor 1because of a tetra-alanine substitution in the protease domain (R. J.Stewart et. al. J. Biol. Chem. 275 (2000) pp. 10112-10120). TNK-tpA ison the market as Tenecteplase® (Boehringer Ingelheim) and can beadministered as a single intravenous bolus, while tPA has to beadministered as a bolus followed by an infusion.

Activated Protein C (APC) is a modulator of the coagulation andinflammation associated with severe sepsis. Activated Protein C isconverted from its inactive precursor (protein C) by thrombin coupled tothrombomodulin. This complex cleaves off a short N-terminal activationpeptide form the heavy chain of protein C, resulting in the activatedprotein C. Drotrecogin alpha (activated) is a recombinant humanactivated protein C (rhAPC) with an amino acid sequence identical toplasma derived activated protein C and with similar properties.Activated protein C is marketed by Eli Lilly as Xigris®. It is producedin a human cell line (HEK293), into which the protein C expressionvectors were introduced. This particular cell line was used due to itsability to perform the correct series of complex post-translationalmodifications that are required for functional activity. Recombinanthuman activated protein C is a 2-chain glycoprotein containing 4N-glycosylation sites and 12 disulfide bonds. The heavy chain contains250 amino acids, of which seven residues are cysteines and it has threeN-linked glycosylation sites (Asn-248, Asn-313 and Asn-329). The sevencysteine residues form three disulfide bonds within the heavy chain andone disulfide bond between the chains. The light chain contains oneN-linked glycosylation site (Asn-97) and 17 cysteine residues, whichform eight disulfide bonds within the light chain and one disulfide bondto the heavy chain. The first nine glutamic acids on the light chain aregamma carboxylated (Gla) and aspartic acid 71 is beta hydroxylated.rhAPC has an identical amino acid sequence to the human plasma-derivedactivated protein C, but differs from the latter in its glycosylationpattern. Activated protein C is a protease belonging to the serineprotease family and plays a major role in the regulation of coagulation.Basis for the antithrombotic function of activated protein C is itsability to inhibit thrombin function. In addition, activated protein Cis an important modulator of inflammation associated with severe sepsis.Endogenous serine protease inhibitors are natural inhibitors foractivated protein C, causing activated protein C to have a very shortcirculatory activity half-life (less than 30 min) in vivo. Clearance ofactivated protein C from the circulation is mediated by a combination ofat least three processes including the inhibition of the enzymaticactivity of activated protein C by endogenous protease inhibitors, theclearance of activated protein C and/or activated protein C-serineprotease inhibitor complexes by organs such as liver and kidney, and thedegradation of activated protein C and/or activated protein C-serineprotease inhibitor complexes by circulating or tissue proteases. Phase Iclinical studies with 24 h-infusion at 24 μg/kg/h resulted in a steadystate plasma concentration of 70 ng/ml. The half-life of rhAPC measuredat the end of an infusion was 0.5-1.9 h. Plasma rhAPC concentrationsfell below the detection limit of 10 ng/ml within 2 h after terminationof the infusion. Due to its short physiological and pharmacokinetichalf-life, activated protein C is continuously infused at a certain rateto maintain the desired plasma concentration in clinical use in sepsistherapy. Some effort is made to improve the pharmacokinetic profile ofactivated protein C. For example D. T. Berg et. al. Proc. Natl. Acad.Sci. USA 100 (2003) pp. 4423-4428, describe an engineered variant ofactivated protein C with a prolonged plasma half-life.

In the context of the present invention, the term “hydroxyalkyl starch”(HAS) refers to a starch derivative which has been substituted by atleast one hydroxyalkyl group. A preferred hydroxyalkyl starch of thepresent invention has a constitution according to formula (I)

wherein the reducing end of the starch molecule is shown in thenon-oxidized form and the terminal saccharide unit is shown in theacetal form which, depending on e.g. the solvent, may be in equilibriumwith the aldehyde form.

The term hydroxyalkyl starch as used in the present invention is notlimited to compounds where the terminal carbohydrate moiety compriseshydroxyalkyl groups R₁, R₂, and/or R₃ as depicted, for the sake ofbrevity, in formula (I), but also refers to compounds in which at leastone hydroxy group present anywhere, either in the terminal carbohydratemoiety and/or in the remaining part of the starch molecule, HAS′, issubstituted by a hydroxyalkyl group R₁, R₂, or R₃.

Hydroxyalkyl starch comprising two or more different hydroxyalkyl groupsare also possible.

The at least one hydroxyalkyl group comprised in HAS may contain two ormore hydroxy groups. According to a preferred embodiment, the at leastone hydroxyalkyl group comprised in HAS contains one hydroxy group.

The expression “hydroxyalkyl starch” also includes derivatives whereinthe alkyl group is mono- or polysubstituted. In this context, it ispreferred that the alkyl group is substituted with a halogen, especiallyfluorine, or with an aryl group. Furthermore, the terminal hydroxy groupof a hydroxyalkyl group may be esterified or etherified.

Furthermore, instead of alkyl, also linear or branched substituted orunsubstituted alkene groups may be used.

Hydroxyalkyl starch is an ether derivative of starch. Besides of saidether derivatives, also other starch derivatives can be used in thecontext of the present invention. For example, derivatives are usefulwhich comprise esterified hydroxy groups. These derivatives may be e.g.derivatives of unsubstituted mono- or dicarboxylic acids with 2-12carbon atoms or of substituted derivatives thereof. Especially usefulare derivatives of unsubstituted monocarboxylic acids with 2-6 carbonatoms, especially derivatives of acetic acid. In this context, acetylstarch, butyryl starch and propinoyl starch are preferred.

Furthermore, derivatives of unsubstituted dicarboxylic acids with 2-6carbon atoms are preferred.

In the case of derivatives of dicarboxylic acids, it is useful that thesecond carboxy group of the dicarboxylic acid is also esterified.Furthermore, derivatives of monoalkyl esters of dicarboxylic acids arealso suitable in the context of the present invention.

For the substituted mono- or dicarboxylic acids, the substitute groupsmay be preferably the same as mentioned above for substituted alkylresidues.

Techniques for the esterification of starch are known in the art (seee.g. Klemm D. et al, Comprehensive Cellulose Chemistry Vol. 2, 1998,Whiley-VCH, Weinheim, N.Y., especially chapter 4.4, Esterification ofCellulose (ISBN 3-527-29489-9).

According to a preferred embodiment of the present invention,hydroxyalkyl starch according to formula (I) is employed.

In formula (I), the saccharide ring described explicitly and the residuedenoted as HAS′ together represent the preferred hydroxyalkyl starchmolecule. The other saccharide ring structures comprised in HAS′ may bethe same as or different from the explicitly described saccharide ring.

As far as the residues R₁, R₂ and R₃ according to formula (I) areconcerned there are no specific limitations. According to a preferredembodiment, R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms in the respective alkylresidue or a group (CH₂CH₂O)_(n)—H, wherein n is an integer, preferably1, 2, 3, 4, 5 or 6. Hydrogen and hydroxyalkyl groups having of from 2 to10 are preferred. More preferably, the hydroxyalkyl group has from 2 to6 carbon atoms, more preferably from 2 to 4 carbon atoms, and even morepreferably from 2 to 4 carbon atoms. “Hydroxyalkyl starch” thereforepreferably comprises hydroxyethyl starch, hydroxypropyl starch andhydroxybutyl starch, wherein hydroxyethyl starch and hydroxypropylstarch are particularly preferred and hydroxyethyl starch is mostpreferred.

The alkyl, aryl, aralkyl and/or alkaryl group may be linear or branchedand optionally suitably substituted.

Therefore, the present invention also relates to a method as describedabove wherein R₁, R₂ and R₃ are independently hydrogen or a linear orbranched hydroxyalkyl group with from 1 to 6 carbon atoms.

Thus, R₁, R₂ and R₃ preferably may be hydroxyhexyl, hydroxypentyl,hydroxybutyl, hydroxypropyl such as 2-hydroxypropyl, 3-hydroxypropyl,2-hydroxyisopropyl, hydroxyethyl such as 2-hydroxyethyl, hydrogen andthe 2-hydroxyethyl group being especially preferred.

Therefore, the present invention also relates to a method and aconjugate as described above wherein R₁, R₂ and R₃ are independentlyhydrogen or a 2-hydroxyethyl group, an embodiment wherein at least oneresidue R₁, R₂ and R₃ being 2-hydroxyethyl being especially preferred.

Hydroxyethyl starch (HES) is most preferred for all embodiments of thepresent invention.

Therefore, the present invention relates to the method and the conjugateas described above, wherein the polymer is hydroxyethyl starch and thepolymer derivative is a hydroxyethyl starch derivative.

Hydroxyethyl starch (HES) is a derivative of naturally occurringamylopectin and is degraded by alpha-amylase in the body. HES is asubstituted derivative of the carbohydrate polymer amylopectin, which ispresent in corn starch at a concentration of up to 95% by weight. HESexhibits advantageous biological properties and is used as a bloodvolume replacement agent and in hemodilution therapy in the clinics(Sommermeyer et al., 1987, Krankenhauspharmazie, 8(8), 271-278; andWeidler et al., 1991, Arzneim.-Forschung/Drug Res., 41, 494-498).

Amylopectin consists of glucose moieties, wherein in the main chainalpha-1,4-glycosidic bonds are present and at the branching sitesalpha-1,6-glycosidic bonds are found. The physical-chemical propertiesof this molecule are mainly determined by the type of glycosidic bonds.Due to the nicked alpha-1,4-glycosidic bond, helical structures withabout six glucose-monomers per turn are produced. The physico-chemicalas well as the biochemical properties of the polymer can be modified viasubstitution. The introduction of a hydroxyethyl group can be achievedvia alkaline hydroxyethylation. By adapting the reaction conditions itis possible to exploit the different reactivity of the respectivehydroxy group in the unsubstituted glucose monomer with respect to ahydroxyethylation. Owing to this fact, the skilled person is able toinfluence the substitution pattern to a limited extent.

HES is mainly characterized by the molecular weight distribution and thedegree of substitution. There are two possibilities of describing thesubstitution degree:

-   1. The degree of substitution can be described relatively to the    portion of substituted glucose monomers with respect to all glucose    moieties.-   2. The degree of substitution can be described as the molar    substitution, wherein the number of hydroxyethyl groups per glucose    moiety are described.

In the context of the present invention, the degree of substitution,denoted as DS, relates to the molar substitution, as described above(see also Sommermeyer et al., 1987, Krankenhauspharmazie, 8(8), 271-278,as cited above, in particular p. 273).

HES solutions are present as polydisperse compositions, wherein eachmolecule differs from the other with respect to the polymerisationdegree, the number and pattern of branching sites, and the substitutionpattern. HES is therefore a mixture of compounds with differentmolecular weight. Consequently, a particular HES solution is determinedby average molecular weight with the help of statistical means. In thiscontext, M_(n) is calculated as the arithmetic mean depending on thenumber of molecules. Alternatively, M_(w) (or MW), the weight mean,represents a unit which depends on the mass of the HES.

In the context of the present invention, hydroxyethyl starch maypreferably have a mean molecular weight (weight mean) of from 1 to 300kD. Hydroxyethyl starch can further exhibit a preferred molar degree ofsubstitution of from 0.1 to 3, preferably 0.1 to 2, more preferred, 0.1to 0.9, preferably 0.1 to 0.8, and a preferred ratio between C₂:C₆substitution in the range of from 2 to 20 with respect to thehydroxyethyl groups.

The term “mean molecular weight” as used in the context of the presentinvention relates to the weight as determined according to theLALLS-(low angle laser light scattering)-GPC method as described inSommermeyer et al., 1987, Krankenhauspharmazie, 8(8), 271-278; andWeidler et al., 1991, Arzneim.-Forschung/Drug Res., 41, 494-498. Formean molecular weights of 10 kD and smaller, additionally, thecalibration was carried out with a standard which had previously beenqualified by LALLS-GPC.

According to a preferred embodiment of the present invention, the meanmolecular weight of hydroxyethyl starch employed is from 1 to 300 kD,preferably from 2 to 200 kD, more preferably of from 3 to 100 kD, morepreferably of from 4 to 70 kD.

An example of HES having a mean molecular weight of about 130 kD is aHES with a degree of substitution of 0.2 to 0.8 such as 0.2, 0.3, 0.4,0.5, 0.6, 0.7, or 0.8, preferably of 0.4 to 0.7 such as 0.4, 0.5, 0.6,or 0.7.

An example for HES with a mean molecular weight of about 130 kD isVoluven® from Fresenius. Voluven® is an artifical colloid, employed,e.g., for volume replacement used in the therapeutic indication fortherapy and prophylaxis of hypovolaemia. The characteristics of Voluven®are a mean molecular weight of 130,000+/−20,000 D, a molar substitutionof 0.4 and a C2:C6 ratio of about 9:1.

Therefore, the present invention also relates to a method and toconjugates as described above wherein the hydroxyalkyl starch ishydroxyethyl starch having a mean molecular weight of from 4 to 100 kD,preferably 4 to 70 kD.

Preferred ranges of the mean molecular weight are, e.g., 4 to 70 kD or10 to 70 kD or 12 to 70 kD or 18 to 70 kD or 50 to 70 kD or 4 to 50 kDor 10 to 50 kD or 12 to 50 kD or 18 to 50 kD or 4 to 18 kD or 10 to 18kD or 12 to 18 kD or 4 to 12 kD or 10 to 12 kD or 4 to 10 kD.

According to particularly preferred embodiments of the presentinvention, the mean molecular weight of hydroxyethyl starch employed isin the range of from more than 4 kD and below 70 kD, such as about 10kD, or in the range of from 9 to 10 kD or from 10 to 11 kD or from 9 to11 kD, or about 12 kD, or in the range of from 11 to 12 kD or from 12 to13 kD or from 11 to 13 kD, or about 18 kD, or in the range of from 17 to18 kD or from 18 to 19 kD or from 17 to 19 kD, or about 30 kD, or in therange of from 29 to 30, or from 30 to 31 kD, or about 50 kD, or in therange of from 49 to 50 kD or from 50 to 51 kD or from 49 to 51 kD.

As to the upper limit of the molar degree of substitution (DS), valuesof up to 3.0 such as 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8,1.9 or 2.0 are also possible, values of below 2.0 being preferred,values of below 1.5 being more preferred, values of below 1.0 such as0.7, 0.8 or 0.9 being still more preferred.

Therefore, preferred ranges of the molar degree of substitution are from0.1 to 2 or from 0.1 to 1.5 or from 0.1 to 1.0 or from 0.1 to 0.9 orfrom 0.1 to 0.8. More preferred ranges of the molar degree ofsubstitution are from 0.2 to 2 or from 0.2 to 1.5 or from 0.2 to 1.0 orfrom 0.2 to 0.9 or from 0.2 to 0.8. Still more preferred ranges of themolar degree of substitution are from 0.3 to 2 or from 0.3 to 1.5 orfrom 0.3 to 1.0 or from 0.3 to 0.9 or from 0.3 to 0.8. Even morepreferred ranges of the molar degree of substitution are from 0.4 to 2or from 0.4 to 1.5 or from 0.4 to 1.0 or from 0.4 to 0.9 or from 0.4 to0.8.

As far as the degree of substitution (DS) is concerned, DS is preferablyat least 0.1, more preferably at least 0.2, and more preferably at least0.4. Preferred ranges of DS are from 0.1 to 0.8, more preferably from0.2 to 0.8, more preferably from 0.3 to 0.8 and even more preferablyfrom 0.4 to 0.8, still more preferably from 0.1 to 0.7, more preferablyfrom 0.2 to 0.7, more preferably from 0.3 to 0.7 and more preferablyfrom 0.4 to 0.7. Particularly preferred values of DS are, e.g., 0.1,0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8, with 0.2, 0.3, 0.4, 0.5, 0.6, 0.7or 0.8 being more preferred, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 being evenmore preferred, 0.4, 0.5, 0.6, 0.7 or 0.8 being still more preferredand, e.g. 0.4 and 0.7 being particularly preferred.

In the context of the present invention, a given value of the molardegree of substitution such as 0.8 may be the exact value or may beunderstood as being in a range of from 0.75 to 0.84. Therefore, forexample, a given value of 0.1 may be the exact value of 0.1 or be in therange of from 0.05 to 0.14, a given value of 0.4 may be the exact valueof 0.4 or in the range of from 0.35 to 0.44, or a given value of 0.7 maybe the exact value of 0.7 or be in the range of from 0.65 to 0.74.

Particularly preferred combinations of molecular weight of thehydroxyalkyl starch, preferably hydroxyethyl starch, and its degree ofsubstitution DS are, e.g., 10 kD and 0.4 or 10 kD and 0.7 or 12 kD and0.4 or 12 kD and 0.7 or 18 kD and 0.4 or 18 kD and 0.7 or 30 kD and 0.4or 30 kD and 0.7, or 50 kD and 0.4 or 50 kD and 0.7 or 100 kD and 0.7.

As far as the ratio of C₂:C₆ substitution is concerned, saidsubstitution is preferably in the range of from 2 to 20, more preferablyin the range of from 2 to 15 and even more preferably in the range offrom 3 to 12.

According to a further embodiment of the present invention, alsomixtures of hydroxyethyl starches may be employed having different meanmolecular weights and/or different degrees of substitution and/ordifferent ratios of C₂:C₆ substitution. Therefore, mixtures ofhydroxyethyl starches may be employed having different mean molecularweights and different degrees of substitution and different ratios ofC₂:C₆ substitution, or having different mean molecular weights anddifferent degrees of substitution and the same or about the same ratioof C₂:C₆ substitution, or having different mean molecular weights andthe same or about the same degree of substitution and different ratiosof C₂:C₆ substitution, or having the same or about the same meanmolecular weight and different degrees of substitution and differentratios of C₂:C₆ substitution, or having different mean molecular weightsand the same or about the same degree of substitution and the same orabout the same ratio of C₂:C₆ substitution, or having the same or aboutthe same mean molecular weights and different degrees of substitutionand the same or about the same ratio of C₂:C₆ substitution, or havingthe same or about the same mean molecular weight and the same or aboutthe same degree of substitution and different ratios of C₂:C₆substitution, or having about the same mean molecular weight and aboutthe same degree of substitution and about the same ratio of C₂:C₆substitution.

In different conjugates and/or different methods according to thepresent invention, different hydroxyalkyl starches, preferably differenthydroxyethyl starches and/or different hydroxyalkyl starch mixtures,preferably different hydroxyethyl starch mixtures, may be employed.

According to one embodiment of the present invention, the functionalgroup Z of the protein is an aldehyde group or a keto group. Therefore,the present invention relates to a method and conjugates as describedabove, wherein the functional group Z of the protein is an aldehydegroup or a keto group.

While there are no general restrictions as to the location of thealdehyde or keto group within the protein, the aldehyde or keto groupis, according to a preferred embodiment of the present invention,located in a carbohydrate side chain of the protein. Therefore, in thecontext of this embodiment, a glycosylated protein is employed.

As glycosylated protein, glycosylated forms of IFN beta such as naturalhuman IFN beta or IFN beta 1a, natural or eucaryotic cell derivedhGM-CSF containing both N- and O-glycans, recombinant human activatedprotein C (rhAPC) being a 2-chain glycoprotein containing 4N-glycosylation sites, human tPA (htPA) or recombinant human tPA (rhtPA)such as type I tPA having N-linked oligosaccharides at amino acidsAsn117, Asn184 and Asn448 or type II tPA being glycosylated at Asn117and Asn448, plasma derived A1AT or recombinant human A1AT (pdA1AT orrhA1AT), recombinant human AT III (rhAT III), factor VII, factor VIIIand factor IX are preferred.

Glycosylated forms of IFN beta, AT III and GM-CSF are especiallypreferred.

In the context of the present invention, the term “glycosylatedprotein”, i.e. a protein having a “carbohydrate side chain” refers toproteins comprising carbohydrate moieties such as hydroxyaldehydes orhydroxyketones as well as to chemical modifications thereof (see RomppChemielexikon, Thieme Verlag Stuttgart, Germany, 9^(th) edition 1990,Volume 9, pages 2281-2285 and the literature cited therein).Furthermore, it also refers to derivatives of naturally occurringcarbohydrate moieties like, galactose, N-acetylneuramic acid, andN-acetylgalactosamine) and the like.

In an even more preferred embodiment, the aldehyde group or the ketogroup is part of a galactose residue of the carbohydrate side chain.This galactose residue can be made available for reaction with thefunctional group A comprised in the polymer or polymer derivative byremoval of terminal sialic acids, followed by oxidation, as describedhereinunder.

In a still further preferred embodiment, the polymer or polymerderivative comprising functional group A is linked to a sialic acidresidue of the carbohydrate side chains, preferably the terminal sialicacid residue of the carbohydrate side chain.

Oxidation of terminal carbohydrate moieties can be performed eitherchemically or enzymatically.

Methods for the chemical oxidation of carbohydrate moieties ofpolypeptides are known in the art and include the treatment withperiodate (Chamow et al., 1992, J. Biol. Chem., 267, 15916-15922).

By chemically oxidizing, it is in principle possible to oxidize anycarbohydrate moiety, being terminally positioned or not. However, bychoosing mild reaction conditions it is possible to preferably oxidizethe terminal sialic acid of a carbohydrate side chain to give thealdehyde group or the keto group.

According to one embodiment of the present invention, said mild reactionconditions relate to reacting the protein with a suitable aqueousperiodate solution, having a preferred periodate concentration in therange of from 1 to 50 mM, more preferably of from 1 to 25 mM andespecially preferably of from 1 to 10 mM such as about 1 mM, and at apreferred reaction temperature of from 0 to 40° C. and especiallypreferably of from 0 to 21° C. such as about 0° C., and for a preferredreaction time of from 5 min to 5 h, more preferably from 10 min to 2 hand especially preferably from 10 min. to 1 h such as about 1 h. Thepreferred molar ratio of periodate:protein is from 1:200 to 1:1 and morepreferably from 1:50 to 1:5. such as about 15:1.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein, prior to the reaction of theprotein and the polymer or polymer derivative, a glycosylated protein isreacted with a periodate solution to give a protein having an aldehydegroup or a keto group located in the oxidized carbohydrate side chain,said reaction preferably being carried out at mild oxidation reactions.The term “mild reaction conditions” as used in this context refers to,e.g., to a 1 mM periodate solution and a reaction temperature of 0° C.in contrast to harsh conditions such as a 10 mM periodate solution and areaction temperature of 20 to 25° C.

Alternatively, the carbohydrate side chain may be oxidizedenzymatically. Enzymes for the oxidation of the individual carbohydrateside chain are known in the art, e.g. in the case of galactose theenzyme is galactose oxidase. If it is intended to oxidize terminalgalactose moieties, it will be eventually necessary to remove terminalsialic acids (partially or completely) if the polypeptide has beenproduced in cells capable of attaching sialic acids to carbohydratechains, e.g. in mammalian cells or in cells which have been geneticallymodified to be capable of attaching sialic acids to carbohydrate chains.Chemical or enzymatic methods for the removal of sialic acids are knownin the art (Chaplin and Kennedy (eds.), 1996, Carbohydrate Analysis: apractical approach, especially Chapter 5 Montreuill, Glycoproteins,pages 175-177; IRL Press Practical approach series (ISBN0-947946-44-3)).

According to another preferred embodiment of the present invention, thealdehyde group or keto group may be located at the N terminus of theprotein and is accessible by suitable oxidation. Especially in the casethat a hydroxy group-containing amino acid is located at the N terminusof the protein at position −1, such as threonine or serine, oxidation ofsaid N-terminal amino acid can be carried out leading to said keto groupor an aldehyde group, preferably an aldehyde group. As method for thechemical oxidation of the suitable N-terminal amino acid, anyconceivable method may be applied, with the oxidation with periodatebeing preferred, with mild oxidation conditions being especiallypreferred.

According to a further preferred embodiment of the present invention,said mild reaction conditions relate to reacting the protein with asuitable aqueous periodate solution, having a preferred periodateconcentration in the range of from 1 to 50 mM, more preferably of from 1to 25 mM and especially preferably of from 1 to 10 mM such as about 1mM, and at a preferred reaction temperature of from 0 to 40° C. andespecially preferably of from 0 to 21° C. such as about 0° C., and for apreferred reaction time of from 5 min to 5 h, more preferably from 10min to 2 h and especially preferably from 10 min. to 1 h such as about 1h. The preferred molar ratio of periodate:protein is from 1:200 to 1:1and more preferably from 1:50 to 1:5, such as about 15:1.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the aldehyde group or the ketogroup is located in a carbohydrate side chain of the protein and/or atthe N-terminal group of the protein.

The oligosaccharide pattern of proteins produced in eukaryotic cellsthus having been posttranslationally glycosylated, are not identical tothe human derived proteins. Moreover, many glycosylated proteins do nothave the desired number of terminal sialic acid residues masking afurther carbohydrate moiety such as a galactose residue. Those furthercarbohydrate moieties such as a galactose residue, however, if notmasked, are possibly responsible for disadvantages such as a shorterplasma half-life of the protein in possible uses of the protein as amedicament It was surprisingly found that by providing a proteinconjugate formed by a hydroxyalkyl starch polymer, preferably ahydroxyethyl starch polymer, which is covalently linked, e.g. via anoxime linkage as disclosed hereinunder, to a carbohydrate moiety of acarbohydrate side chain of the protein, either directly or via at leastone linker compounds such as one or two linker compounds, it is possibleto overcome at least the above mentioned disadvantage. Hence it isbelieved that by coupling a hydroxyalkyl starch polymer or derivativethereof, preferably a hydroxyethyl starch polymer or a derivativethereof, to at least one carbohydrate side chain of a glycosylatedprotein, the lack of suitable terminal carbohydrate residues located ata carbohydrate side chain is compensated. According to another aspect ofthe invention, providing the respective conjugate with a hydroxyalkylstarch polymer or derivative thereof, preferably a hydroxyethyl starchpolymer or a derivative thereof, coupled to the oxidized carbohydratemoiety as described above, does not only compensate the disadvantage butprovides a protein conjugate having better characteristics in thedesired field of use than the respective naturally occurring protein.Therefore, the respective conjugates according to the invention have acompensational and even a synergistic effect on the protein. It alsopossible that even proteins which are identical to human proteins orwhich are human proteins do not have the desired number of suitablemasking terminal carbohydrate residues such as silaic acid residues atnaturally occurring carbohydrate moieties. In such cases, providing therespective conjugate with a hydroxyalkyl starch polymer or derivativethereof, preferably a hydroxyethyl starch polymer or a derivativethereof, coupled to the oxidized carbohydrate moiety as described above,does not only overcome and compensate a disadvantage of an artificiallyproduced protein, but improves the characteristics of the a naturalnaturally occurring protein. As to the functional group of thehydroxyalkyl starch, preferably hydroxyethyl starch, or a derivativethereof, which is coupled to the aldehyde group or keto group of theoxidized carbohydrate moiety of the protein, reference is made to thefunctional groups A as disclosed hereinunder. This general concept isnot only applicable to glycosylated G-CSF, but principally to allglycosylated proteins having said lack of terminal carbohydrateresidues. Among others, erythropoietin (EPO), interferone beta 1a (IFNbeta 1a), ATIII, factor VIII, alphal-antitrypsin (A1AT), htPA, or GM-CSFmay be mentioned.

Therefore, the present invention also relates to the use of hydroxyalkylstarch, preferably hydroxyethyl starch, or a derivative thereof, forcompensating the lack of terminal carbohydrate residues, preferablysialic acid residues, in naturally occurring or posttranslationallyattached carbohydrate moieties of a protein, by covalently coupling thestarch or derivative thereof to at least one oxidized carbohydratemoiety of a protein having at least one keto or aldehyde group.

Accordingly, the present invention also relates to a method forcompensating the lack of terminal carbohydrate residues, preferablysialic acid residues, in naturally occurring or posttranslationallyattached carbohydrate moieties of a protein, by covalently couplinghydroxyalkyl starch, preferably hydroxyethyl starch, or a derivativethereof to at least one oxidized carbohydrate moiety of a protein havingat least one keto or aldehyde group, preferably via an oxime linkage.

Moreover, the present invention also relates to a conjugate formed bycovalent linkage of a hydroxyalkyl starch, preferably hydroxyethylstarch, or a derivative thereof, to at least one oxidized carbohydratemoiety of a protein, said protein being either isolated from naturalsources or produced by expression in eukaryotic cells, such asmammalian, insect or yeast cells, said carbohydrate moiety having atleast one keto or aldehyde group, wherein the conjugate has in thedesired field of use, preferably the use as medicament, the same orbetter characteristics than the respective unmodified protein.

In case functional group Z of the protein is an aldehyde group or a ketogroup, functional group A of the polymer or the derivative thereofcomprises an amino group according to the structure —NH—.

Therefore, the present invention also relates to a method and aconjugate as described above wherein the functional group A capable ofbeing reacted with the optionally oxidized reducing end of the polymer,comprises an amino group according to structure —NH—.

According to one preferred embodiment of the present invention, thisfunctional group A is a group having the structure R′—NH— where R′ ishydrogen or a alkyl, cycloalkyl, aryl, aralkyl, arylcycloalkyl, alkarylor cycloalkylaryl residue where the cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl or cycloalkylaryl residue may be linked directlyto the NH group or, according to another embodiment, may be linked by anoxygen bridge to the NH group. The alkyl, cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl, or cycloalkylaryl residues may be suitablysubstituted. As preferred substituents, halogenes such as F, Cl or Brmay be mentioned. Especially preferred residues R′ are hydrogen, alkyland alkoxy groups, and even more preferred are hydrogen andunsubstituted alkyl and alkoxy groups.

Among the alkyl and alkoxy groups, groups with 1, 2, 3, 4, 5, or 6 Catoms are preferred. More preferred are methyl, ethyl, propyl,isopropyl, methoxy, ethoxy, propoxy, and isopropoxy groups. Especiallypreferred are methyl, ethyl, methoxy, ethoxy, and particular preferenceis given to methyl or methoxy.

Therefore, the present invention also relates to a method and aconjugate as described above wherein R′ is hydrogen or a methyl or amethoxy group.

According to another preferred embodiment of the present invention, thefunctional group A has the structure R′—NH—R″— where R″ preferablycomprises the structure unit —NH— and/or the structure unit —(C=G)-where G is O or S, and/or the structure unit —SO₂—. According to morepreferred embodiments, the functional group R″ is selected from thegroup consisting of where, if G is present twice, it is independently Oor S.

Therefore, preferred functional groups A comprising an amino group —NH₂,are, e.g.,

wherein G is O or S and, if present twice, independently O or S, and R′is methyl.

Especially preferred functional groups A comprising an amino group areaminooxy groups

H₂N—O— being particularly preferred, and the hydrazido group

where G is preferably O.

Therefore, the present invention also relates to a method as describedabove, wherein the functional group Z of the protein is an aldehydegroup or a keto group, and the functional group A is an aminooxy groupor a hydrazido group. According to an especially preferred embodiment ofthe present invention, A is an aminooxy group.

Thus, the present invention also relates to a conjugate, as describedabove, wherein the functional group Z of the protein is an aldehydegroup or a keto group, and the functional group A is an aminooxy groupor a hydrazido group. According to an especially preferred embodiment ofthe present invention, A is an aminooxy group.

When reacting the aminooxy group of the polymer or polymer derivativewith the aldehyde group or keto group of the protein, an oxime linkageis formed.

Therefore, the present invention also relates to a conjugate asdescribed above, wherein the covalent linkage between the protein andthe polymer or polymer derivative is an oxime linkage formed by thereaction of functional group Z of the protein, said functional group Zbeing an aldehyde group or a keto group, and functional group A of thepolymer or polymer derivative, said functional group A being an aminooxygroup.

When reacting the hydrazido group of the polymer or polymer derivativewith the aldehyde group or keto group of the protein, a hydrazonelinkage is formed.

Therefore, the present invention also relates to a conjugate asdescribed above, wherein the covalent linkage between the protein andthe polymer or polymer derivative is a hydrazone linkage formed by thereaction of functional group Z of the protein, said functional group Zbeing an aldehyde group or a keto group, and functional group A of thepolymer or polymer derivative, said functional group A being a hydrazidogroup.

In order to introduce functional group A into the polymer, no specificrestrictions exist given that a polymer derivative results comprisingfunctional group A.

According to a preferred embodiment of the present invention, thefunctional group A is introduced into the polymer by reacting thepolymer with an at least bifunctional compound, one functional group ofwhich is capable of being reacted with at least one functional group ofthe polymer, and at least one other functional group of the at leastbifunctional compound being functional group A or being capable of beingchemically modified to give functional group A.

According to a still further preferred embodiment, the polymer isreacted with the at least bifunctional compound at its optionallyoxidized reducing end.

In case the polymer is reacted with its non-oxidized reducing end, thepolymer preferably has the constitution

wherein in formula (I), the aldehyde form of the non-oxidized reducingend is included.

In case the polymer is reacted with its oxidized reducing end, thepolymer preferably has the constitution according to formula (IIa)

and/or according to formula (IIb)

The oxidation of the reducing end of the polymer, preferablyhydroxyethyl starch, may be carried out according to each method orcombination of methods which result in compounds having theabove-mentioned structures (IIa) and/or (IIb).

Although the oxidation may be carried out according to all suitablemethod or methods resulting in the oxidized reducing end of hydroxyalkylstarch, it is preferably carried out using an alkaline iodine solutionas described, e.g., in DE 196 28 705 A1 the respective contents of which(example A, column 9, lines 6 to 24) is incorporated herein byreference.

As functional group of the at least bifunctional compound which iscapable of being reacted with the optionally oxidized reducing end ofthe polymer, each functional group may be used which is capable offorming a chemical linkage with the optionally oxidized reducing end ofthe hydroxyalkyl starch.

According to a preferred embodiment of the present invention, thisfunctional group comprises the chemical structure —NH—.

Therefore, the present invention also relates to a method and aconjugate as described above wherein the functional group of the atleast bifunctional compound, said functional group being capable ofbeing reacted with the optionally oxidized reducing end of the polymer,comprises the structure —NH—.

According to one preferred embodiment of the present invention, thisfunctional group of the at least bifunctional compound is a group havingthe structure R′—NH— where R′ is hydrogen or a alkyl, cycloalkyl, aryl,aralkyl, arylcycloalkyl, alkaryl or cycloalkylaryl residue where thecycloalkyl, aryl, aralkyl, arylcycloalkyl, alkaryl or cycloalkylarylresidue may be linked directly to the NH group or, according to anotherembodiment, may be linked by an oxygen bridge to the NH group. Thealkyl, cycloalkyl, aryl, aralkyl, arylcycloalkyl, alkaryl, orcycloalkylaryl residues may be suitably substituted. As preferredsubstituents, halogenes such as F, Cl or Br may be mentioned. Especiallypreferred residues R′ are hydrogen, alkyl and alkoxy groups, and evenmore preferred are hydrogen and unsubstituted alkyl and alkoxy groups.

Among the alkyl and alkoxy groups, groups with 1, 2, 3, 4, 5, or 6 Catoms are preferred. More preferred are methyl, ethyl, propyl,isopropyl, methoxy, ethoxy, propoxy, and isopropoxy groups. Especiallypreferred are methyl, ethyl, methoxy, ethoxy, and particular preferenceis given to methyl or methoxy.

Therefore, the present invention also relates to a method and aconjugate as described above wherein R′ is hydrogen or a methyl or amethoxy group.

According to another preferred embodiment of the present invention, thefunctional group of the at least bifunctional compound has the structureR′—NH—R″— where R″ preferably comprises the structure unit —NH— and/orthe structure unit —(C=G)- where G is O or S, and/or the structure unit—SO₂—. According to more preferred embodiments, the functional group R″is selected from the group consisting of

where, if G is present twice, it is independently O or S.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the functional group of the atleast bifunctional compound, said functional group being capable ofbeing reacted with the optionally oxidized reducing end of the polymer,is selected from the group consisting of

wherein G is O or S and, if present twice, independently O or S, and R′is methyl.

According to an even more preferred embodiment of the present invention,the functional group of the at least bifunctional compound, saidfunctional group being capable of being reacted with the optionallyoxidized reducing end of the polymer and comprising an amino group, isan aminooxy groups

H₂N—O— being particularly preferred, or the hydrazido group

wherein G is preferably O.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the functional group Z of theprotein is an aldehyde group or a keto group, and the functional groupof the at least bifunctional compound, said functional group beingcapable of being reacted with the optionally oxidized reducing end ofthe polymer, is an aminooxy group or a hydrazido group, preferably anaminooxy group.

Thus, the present invention also relates to a conjugate, as describedabove, wherein the functional group Z of the protein is an aldehydegroup or a keto group, and the functional group of the at leastbifunctional compound, said functional group being capable of beingreacted with the optionally oxidized reducing end of the polymer, is anaminooxy group or a hydrazido group, preferably an aminooxy group.

According to a still further preferred embodiment of the presentinvention, the at least bifunctional compound is reacted with thepolymer at its non-oxidized reducing end.

According to yet another preferred embodiment of the present invention,the at least bifunctional compound which is reacted with the optionallyoxidized reducing end of the polymer, comprises functional group A.

The at least bifunctional compound may be reacted with the polymer firstto give a polymer derivative which is subsequently reacted with theprotein via functional group A. It is also possible to react the atleast bifunctional compound via functional group A with the proteinfirst to give a protein derivative which is subsequently reacted withthe polymer via at least one functional group of the at leastbifunctional compound residue comprised in the protein derivative.

According to a preferred embodiment of the present invention, the atleast bifunctional compound is reacted with the polymer first.

Therefore, the present invention relates to a method and a conjugate asdescribed above, said method further comprising reacting the polymer atits non-oxidized reducing end with an at least bifunctional linkingcompound comprising a functional group capable of reacting with thenon-oxidized reducing end of the polymer and a group A, prior to thereaction of the polymer derivative comprising A and the proteincomprising Z.

The term “the polymer (or HAS) is reacted via the reducing end” or “thepolymer (or HAS) is reacted via the selectively oxidized reducing end”as used in the context of the present invention relates to a processaccording to which the polymer (or HAS) is reacted predominantly via its(selectively oxidized) reducing end.

This term “predominantly via its (selectively oxidized) reducing end”relates to processes according to which statistically more than 50%,preferably at least 55%, more preferably at least 60%, more preferablyat least 65%, more preferably at least 70%, more preferably at least75%, more preferably at least 80%, more preferably at least 85%, morepreferably at least 90%, and still more preferably at least 95% such as95%, 96%, 97%, 98%, or 99% of the hydroxyalkyl starch molecules employedfor a given reaction are reacted via at least one (selectively oxidized)reducing end per polymer (or HAS) molecule, wherein a given polymer (orHAS) molecule which is reacted via at least one reducing end can bereacted in the same given reaction via at least one further suitablefunctional group which is comprised in said polymer (or HAS) moleculeand which is not a reducing end. If one or more polymer (or HAS)molecule(s) is (are) reacted via at least one reducing endsimultaneously via at least one further suitable functional group whichis comprised in this (these) polymer (or HAS) molecule(s) and which isnot a reducing end, statistically preferably more than 50%, preferablyat least 55%, more preferably at least 60%, more preferably at least65%, more preferably at least 70%, more preferably at least 75%, morepreferably at least 80%, more preferably at least 85%, more preferablyat least 90%, and still more preferably at least 95% such as 95%, 96%,97%, 98%, or 99% of all reacted functional groups of these polymer (orHAS) molecules, said functional groups including the reducing ends, arereducing ends.

The term “reducing end” as used in the context of the present inventionrelates to the terminal aldehyde group of a polymer (or HAS) moleculewhich may be present as aldehyde group and/or as corresponding acetalfrom. In case the reducing end is oxidized, the aldehyde or acetal groupis in the form of a carboxy group and/or of the corresponding lactone.

The functional group of the at least bifunctional linking compound whichis reacted with the polymer and the functional group A of the at leastbifunctional linking compound which is reacted with functional group Zof the protein may be separated by any suitable spacer. Among others,the spacer may be an optionally substituted, linear, branched and/orcyclic hydrocarbon residue. Generally, the hydrocarbon residue has up to60, preferably up to 40, more preferably up to 20, more preferably up to10, more preferably up to 6 and especially preferably up to 4 carbonatoms. If heteroatoms are present, the separating group comprisesgenerally from 1 to 20, preferably from 1 to 8, more preferably 1 to 6,more preferably 1 to 4 and especially preferably from 1 to 2heteroatoms. As heteroatom, O is preferred. The hydrocarbon residue maycomprise an optionally branched alkyl chain or an aryl group or acycloalkyl group having, e.g., from 5 to 7 carbon atoms, or be anaralkyl group, an alkaryl group where the alkyl part may be a linearand/or cyclic alkyl group. According to an even more preferredembodiment of the present invention, the functional groups are separatedby a linear hydrocarbon chain having 4 carbon atoms. According toanother preferred embodiment of the present invention, the functionalgroups are separated by a linear hydrocarbon chain having 4 carbon atomsand at least one, preferably one heteroatom, particularly preferably anoxygen atom.

According to a further preferred embodiment, the at least bifunctionallinking compound is a homobifunctional linking compound. Therefore, thepresent invention also relates to a method of producing a conjugate asdescribed above, wherein the at least bifunctional linking compound is ahomobifunctional compound.

Thus, with regard to the above mentioned preferred functional groups ofthe linking compound, said homobifunctional linking compound preferablycomprises either two aminooxy groups H₂N—O— or two aminooxy groupsR′—O—NH— or two hydrazido groups H₂N—NH—(C=G)-, the aminooxy groupsH₂N—O— and the hydrazido groups H₂N—NH—(C═O)— being preferred, and theaminooxy groups H₂N—O— being especially preferred.

Among all conceivable homobifunctional compounds comprising twohydrazido groups H₂N—NH—(C═O)—, hydrazides are preferred where the twohydazido groups are separated by a hydrocarbon residue having up to 60,preferably up to 40, more preferably up to 20, more preferably up to 10,more preferably up to 6 and especially preferably up to 4 carbon atoms.More preferably, the hydrocarbon residue has 1 to 4 carbon atoms such as1, 2, 3, or 4 carbon atoms. Most preferably, the hydrocarbon residue has4 carbon atoms. Therefore, a homobifunctional compound according toformula

is preferred.

In the above decribed embodiment where an aldehyde group or a keto groupof the protein is reacted with a compound comprising two hydrazidogroups H₂N—NH—(C═O)—, particularly preferred hydroxyethyl starches are,e.g., hydroxyethyl starches having a mean molecular weight of about 10kD and a DS of about 0.4. Also possible are, e.g., hydroxyethyl starchhaving a mean molecular weight of about 10 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 18 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 50 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 12 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 12 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 18 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 30 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 30 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 50 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 100 kD and a DS of about0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

According to an even more preferred embodiment of the present invention,the bifunctional linking compound is carbohydrazide

In the above described embodiment where an aldehyde group or a ketogroup of the protein is reacted with carbohydrazide, particularlypreferred hydroxyethyl starches are, e.g., hydroxyethyl starches havinga mean molecular weight of about 10 kD and a DS of about 0.4. Alsopossible are, e.g., hydroxyethyl starch having a mean molecular weightof about 10 kD and a DS of about 0.7 or hydroxyethyl starch having amean molecular weight of about 18 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 12 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 12 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 18 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 30 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 30 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

As described above, the present invention also relates to a method and aconjugate as described above, wherein the at least bifunctional linkingcompound is a homobifunctional compound and comprises two aminooxygroups. Hence, the present invention also relates to a method and aconjugate as described above, wherein the at least bifunctional linkingcompound is a homobifunctional compound and comprises two aminooxygroups H₂N—O—.

As described above, the polymer is preferably reacted at its reducingend which is not oxidized prior to the reaction with the bifunctionallinking compound. Therefore, reacting the preferred homobifunctionalcompound comprising two aminooxy groups H₂N—O— with the polymer resultsin a polymer derivative comprising an oxime linkage.

Therefore, since functional group Z of the protein is an aldehyde or aketo group which is preferably reacted with an aminooxy group of thepolymer derivative, the present invention also relates to a conjugate asdescribed above, said conjugate comprising the polymer and the protein,each being covalently linked to a linking compound by an oxime or acyclic aminal linkage.

Among all conceivable homobifunctional compounds comprising two aminooxygroups H₂N—O—, bifunctional compounds are preferred where the twoaminooxy groups are separated by a hydrocarbon residue having from 1 to60, preferably from 1 to 40, more preferably from 1 to 20, morepreferably from 1 to 10, more preferably from 1 to 6 and especiallypreferably 1 to 4 carbon atoms. More preferably, the hydrocarbon residuehas 1 to 4 carbon atoms such as 1, 2, 3, or 4 carbon atoms. Mostpreferably, the hydrocarbon residue has 4 carbon atoms. Even morepreferably, the hydrocarbon residue has at least one heteroatom, morepreferably one heteroatom, and most preferably one oxygen atom. Thecompound O-[2-(2-aminooxy-ethoxy)-ethyl]hydroxyl amine according toformula

is especially preferred.

Therefore, the present invention relates to a conjugate as describedabove, said conjugate having a constitution according to formula

HAS′ preferably being HES′. Particularly preferred hydroxyethyl starchesare, e.g., hydroxyethyl starches having a mean molecular weight of about10 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 10 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 12 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 12 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 18 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 18 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 30 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 30 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 50 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 50 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 100kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

In the above described embodiment where an aldehyde group or a ketogroup of the protein is reacted with a hydroxyamino group of the polymeror polymer derivative, particularly preferred hydroxyethyl starches are,e.g., hydroxyethyl starches having a mean molecular weight of about 10kD and a DS of about 0.4 and hydroxyethyl starch having a mean molecularweight of about 10 kD and a DS of about 0.7 and hydroxyethyl starchhaving a mean molecular weight of about 18 kD and a DS of about 0.4 andhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.7. Also possible are, e.g., hydroxyethylstarch having a mean molecular weight of about 12 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 12 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 18 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 30 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 30 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 50 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 100 kD and a DS of about0.7.

As proteins, glycosylated IFN beta, glycosylated AT III and glycosylatedGM-CSF are especially preferred. Therefore, in case the hydroxyalkylstarch is preferably hydroxyethyl starch, the present invention alsorelates to a conjugate

and/or a conjugate

and/or a conjugate

and/or a conjugate

and/or a conjugate

and/or a conjugate

HES′ especially preferably being derived independently for each proteinfrom hydroxyethyl starch having a mean molecular weight of about 10 kDand a DS of about 0.4 and/or hydroxyethyl starch having a mean molecularweight of about 10 kD and/or a DS of about 0.7 and/or hydroxyethylstarch having a mean molecular weight of about 18 kD and a DS of about0.4 and/or hydroxyethyl starch having a mean molecular weight of about50 kD and a DS of about 0.4 and/or hydroxyethyl starch having a meanmolecular weight of about 50 kD and a DS of about 0.7 and/orhydroxyethyl starch having a mean molecular weight of about 100 kD and aDS of about 0.7.

The reaction of the polymer at its non-oxidized reducing end with thelinking compound, especially in the case said linking compound is ahomobifunctional linking compound comprising two aminooxy groups H₂N—O—,is preferably carried out in an aqueous system.

The term “aqueous system” as used in the context of the presentinvention refers to a solvent or a mixture of solvents comprising waterin the range of from at least 10% per weight, preferably at least 50%per weight, more preferably at least 80% per weight, even morepreferably at least 90% per weight or up to 100% per weight, based onthe weight of the solvents involved. The preferred reaction medium iswater.

According to another embodiment, at least one other solvent may be usedin which HAS, preferably HES is soluble. Examples of these solvents are,e.g., DMF, dimethylacetamide or DMSO.

As far as the temperatures which are applied during the reaction areconcerned, no specific limitations exist given that the reaction resultsin the desired polymer derivative.

In case the polymer is reacted with the homobifunctional linkingcompound comprising two aminooxy groups H₂N—O—, preferablyO-[2-(2-aminooxy-ethoxy)-ethyl]hydroxyl amine, the temperature ispreferably in the range of from 5 to 45° C., more preferably in therange of from 10 to 30° C. and especially preferably in the range offrom 15 to 25° C.

The reaction time for the reaction of the polymer with thehomobifunctional linking compound comprising two aminooxy groups H₂N—O—,preferably O-[2-(2-aminooxy-ethoxy)-ethyl]hydroxyl amine, may be adaptedto the specific needs and is generally in the range of from 1 h to 7 d,preferably in the range of from 1 h to 3 d and more preferably of from 2h to 48 h.

The pH value for the reaction of the polymer with the homobifunctionallinking compound comprising two aminooxy groups H₂N—O—, preferablyO-[2-(2-aminooxy-ethoxy)-ethyl]hydroxyl amine, may be adapted to thespecific needs such as the chemical nature of the reactants. The pHvalue is preferably in the range of from 4.5 to 6.5.

Specific examples of above mentioned reaction conditions are, e.g., areaction temperature of about 25° C. and a pH of about 5.5.

The suitable pH value of the reaction mixture may be adjusted by addingat least one suitable buffer. Among the preferred buffers, sodiumacetate buffer, phosphate or borate buffers may be mentioned.

Once the polymer derivative comprising the polymer and the bifunctionallinking compound linked thereto is formed, it may be isolated from thereaction mixture by at least one suitable method. If necessary, thepolymer derivative may be precipitated prior to the isolation by atleast one suitable method.

If the polymer derivative is precipitated first, it is possible, e.g.,to contact the reaction mixture with at least one solvent or solventmixture other than the solvent or solvent mixture present in thereaction mixture at suitable temperatures, such as, for exampleacetone/ethanol mixtures in suitable volume/volume ratios, such as 1/1v/v or isopropanol at suitable temperatures such as from −20° C. to 50°C. or from 0° C. to 25° C. According to a particularly preferredembodiment of the present invention where an aqueous medium, preferablywater is used as solvent, the reaction mixture is contacted with amixture of 2-propanol at a temperature, preferably in the range of from−20 to +50° C. and especially preferably in the range of from 0 to 25°C.

Isolation of the polymer derivative may be carried out by a suitableprocess which may comprise one or more steps. According to a preferredembodiment of the present invention, the polymer derivative is firstseparated off the reaction mixture or the mixture of the reactionmixture with, e.g., aqueous 2-propanol mixture, by a suitable methodsuch as centrifugation or filtration. In a second step, the separatedpolymer derivative may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation. According to an evenmore preferred embodiment, the separated polymer derivative is firstdialysed, preferably against water, and then lyophilized until thesolvent content of the reaction product is sufficiently low according tothe desired specifications of the product. Lyophilisation may be carriedout at temperature of from 20 to 35° C., preferably of from 20 to 30° C.

The thus isolated polymer derivative is then further reacted, viafunctional group A, with the functional group Z of the protein, Z beingan aldehyde group or a keto group. In the especially preferred case thatA is an aminooxy group H₂N—O— to give an oxime linkage between polymerderivative and protein, the reaction is preferably carried out in anaqueous medium, preferably water, at a preferred temperature in therange of from 0 to 40° C., more preferably from 4 to 25° C. andespecially preferably from 15 to 25° C. The pH value of the reactionmedium is preferably in the range of from 4 to 10, more preferably inthe range of from 5 to 9 and especially preferably in the range of from5 to 7. The reaction time is preferably in the range of from 1 to 72 h,more preferably in the range of from 1 to 48 h and especially preferablyin the range of from 4 to 24 h.

The conjugate may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation.

According to another embodiment of the present invention, the functionalgroup Z of the protein is an amino group and the protein is selectedfrom the group consisting of IFN alpha, IFN beta, GM-CSF, APC, tPA,A1AT, AT III, factor VII, factor VIII and factor IX. Therefore, thepresent invention relates to a method and a conjugate as describedabove, wherein the functional group Z of the protein is an amino groupand the protein is selected from the group consisting of IFN alpha, IFNbeta, GM-CSF, APC, tPA, A1AT, AT III, factor VII, factor VIII and factorIX.

According to an especially preferred embodiment of the presentinvention, the functional group A to be reacted with the functionalgroup Z being an amino group is a reactive carboxy group. Therefore, thepresent invention also relates to a method and a conjugate as describedabove, wherein the functional group Z is an amino group and thefunctional group A of the polymer or the polymer derivative is areactive carboxy group.

According to a first preferred embodiment of the present invention, thereactive carboxy group is introduced into the polymer by selectivelyoxidizing the polymer at its reducing end.

Therefore, the polymer into which the reactive carboxy group isintroduced preferably has the constitution according to formula (IIa)

and/or according to formula (IIb)

The oxidation of the reducing end of the polymer according to formula(I)

preferably hydroxyethyl starch, may be carried out according to eachmethod or combination of methods which result in compounds having theabove-mentioned structures (IIa) and/or (IIb).

Although the oxidation may be carried out according to all suitablemethod or methods resulting in the oxidized reducing end of hydroxyalkylstarch, it is preferably carried out using an alkaline iodine solutionas described, e.g., in DE 196 28 705 A1 the respective contents of which(example A, column 9, lines 6 to 24) is incorporated herein byreference.

Introducing the reactive carboxy group into the polymer which isselectively oxidized at its reducing end may be carried out by allconceivable methods.

The oxidized polymer may be employed as such or as a salt, such as analkali metal salt, preferably as a sodium and/or a potassium salt.

According to a preferred method of the present invention, the polymerwhich is selectively oxidized at its reducing end is reacted at theoxidized reducing end with at least one alcohol, preferably with atleast one acidic alcohol. Still further preferred are acidic alcoholshaving a pK_(A) value in the range of from 6 to 12, more preferably offrom 7 to 11 at 25° C. The molecular weight of the acidic alcohol ispreferably in the range of from 80 to 500 g/mole, more preferably offrom 90 to 300 g/mole and especially preferably of from 100 to 200g/mole.

Suitable acidic alcohols are all alcohols H—O—R_(A) having an acidicproton and are capable of being reacted with the oxidized polymer togive the respective reactive polymer ester, preferably according to theformula

still more preferably according to formula

Preferred alcohols are N-hydroxy succinimides such as N-hydroxysuccinimide or Sulfo-N-hydroxy succinimide, suitably substituted phenolssuch as p-nitrophenol, o,p-dinitrophenol, o,o′-dinitrophenol,trichlorophenol such as 2,4,6-trichlorophenol or 2,4,5-trichlorophenol,trifluorophenol such as 2,4,6-trifluorophenol or 2,4,5-trifluorophenol,pentachlorophenol, pentafluorophenol, or hydroxyazoles such as hydroxybenzotriazole. Especially preferred are N-hydroxy succinimides, withN-hydroxy succinimide and Sulfo-N-hydroxy succinimide being especiallypreferred. All alcohols may be employed alone or as suitable combinationof two or more thereof. In the context of the present invention, it isalso possible to employ a compound which releases the respectivealcohol, e.g. by adding diesters of carbonic acids.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer which is selectivelyoxidised at its reducing end is activated by reacting the oxidisedpolymer with an acidic alcohol, preferably with N-hydroxy succinimideand/or Sulfo-N-hydroxy succinimide.

According to an even more preferred embodiment of the present invention,the polymer which is selectively oxidized at its reducing end is reactedat the oxidized reducing end with at least one carbonic diesterR_(B)—O—(C═O)—O—R_(C), wherein R_(B) and R_(C) may be the same ordifferent. Preferably, this method gives reactive polymers according tothe formula

wherein HAS′ is preferably HES′.

As suitable carbonic diester compounds, compounds may be employed whosealcohol components are independently N-hydroxy succinimides such asN-hydroxy succinimide or Sulfo-N-hydroxy succinimide, suitablysubstituted phenols such as p-nitrophenol, o,p-dinitrophenol,o,o′-dinitrophenol, trichlorophenol such as 2,4,6-trichlorophenol or2,4,5-trichlorophenol, trifluorophenol such as 2,4,6-trifluorophenol or2,4,5-trifluorophenol, pentachlorophenol, pentafluorophenol, orhydroxyazoles such as hydroxy benzotriazole. Especially preferred areN,N′-disuccinimidyl carbonate and Sulfo-N,N′-disuccinimidyl carbonate,with N,N′-disuccinimidyl carbonate being especially preferred.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer which is selectivelyoxidised at its reducing end is activated by reacting the oxidisedpolymer with N,N′-disuccinimidyl carbonate.

The acidic alcohol is reacted with the oxidized polymer or the salt ofthe oxidized polymer at a molar ratio of acidic alcohol:polymerpreferably of from 5:1 to 50:1, more preferably of from 8:1 to 20:1, ata preferred reaction temperature of from 2 to 40° C., more preferably offrom 10 to 30° C. and especially preferably of from 15 to 25° C. Thereaction time is preferably in the range of from 1 to 10 h, morepreferably of from 2 to 5 h, more preferably of from 2 to 4 h andparticularly of from 2 to 3 h.

The carbonic diester compound is reacted with the oxidized polymer orthe salt of the oxidized polymer at a molar ratio of diestercompound:polymer preferably of from 1:1 to 3:1, more preferably of from1:1 to 1.5:1. The reaction time is preferably in the range of from 0.1to 12 h, more preferably of from 0.2 to 6 h, more preferably of from 0.5to 2 h and particularly of from 0.75 to 1.25 h.

According to a preferred embodiment of the present invention, reactingthe oxidized polymer with acidic alcohol and/or carbonic diester iscarried out in at least one aprotic solvent, particularly preferably inan anhydrous aprotic solvent having a water content of not more than 0.5percent by weight, preferably of not more than 0.1 percent by weight.Suitable solvents are, among others, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, dimethyl acetamide (DMA), dimethyl formamide (DMF) andmixtures of two or more thereof. The reaction temperatures arepreferably in the range of from 2 to 40° C., more preferably of from 10to 30° C.

For reacting the oxidized polymer with the at least one acidic alcohol,at least one additional activating agent is employed.

Suitable activating agents are, among others, carbonyldiimidazole,carbodiimides such as diisopropyl carbodiimide (DIC), dicyclohexylcarbodiimides (DCC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC), with dicyclohexyl carbodiimides (DCC) and1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) being especiallypreferred.

Therefore, the present invention also relates to a method and aconjugate as described above, where the polymer which is oxidized at itsreducing end, is reacted with an acidic alcohol in the presence of anadditional activating agent to give the reactive polymer ester.

According to an especially preferred embodiment of the presentinvention, the reaction of the oxidized polymer with carbonic diesterand/or acidic alcohol is carried out at a low base activity which may bedetermined by adding the reaction mixture to water with a volume ratioof water to reaction mixture of 10:1. Prior to the addition, the waterwhich comprises essentially no buffer, has a pH value of 7 at 25° C.After the addition of the reaction mixture and by measuring the pHvalue, the base activity of the reaction mixture is obtained, having avalue of preferably not more than 9.0, more preferably of not more than8.0 and especially preferably of not more than 7.5.

According to a preferred embodiment of the present invention, theoxidized polymer is reacted with N-hydroxy succinimide in dry DMA in theabsence of water with EDC to selectively give the polymer N-hydroxysuccinimide ester according to the formula

more preferably with HAS′ being HES′.

Surprisingly, this reaction does not give by-products resulting fromreactions of EDC with OH groups of HES, and the rearrangement reactionof the O-acyl isourea formed by EDC and the oxidized polymer to therespective N-acyl urea is surprisingly suppressed.

According to another preferred embodiment of the present invention, theoxidized polymer is reacted with N,N′-disuccinimidyl carbonate inanhydrous DMF and in the absence of an activating agent to selectivelygive the polymer N-hydroxy succinimide ester according to the formula

more preferably with HAS′ being HES′.

The reactive polymer as described above is preferentially furtherreacted with at least one amino group of the protein to give an amidelinkage. According to a preferred embodiment of the present invention,the reactive polymer is reacted with one amino group of the protein.

The amino group of the protein can be an amino group of a suitable aminoacid residue of the protein such as a lysin residue or a histidineresidue or the amino group located at the N terminus of the protein.

Therefore, the present relates to a conjugate preferably having aconstitution according to the formula

wherein the N atom of the amide linkage is derived from an amino groupof the protein, with HAS′ preferably being HES′, the hydroxyethyl starchpreferably being hydroxyethyl starch having a mean molecular weight ifabout 10 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight if about 10 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight if about 12 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight if about 12 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight if about 18 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight if about 18 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 30 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 30 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight if about 50 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight if about 50 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 100kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

An especially preferred protein coupled via above-mentioned amidelinkage to hydroxyalkyl starch, preferably hydroxyethyl starch, is ATIII. Therefore, the present invention also relates to a conjugate

wherein the N atom of the amide linkage is derived from an amino groupof AT III and where HAS′ is preferably HES′ and even more preferablyhydroxyethyl starch having a molecular weight of about 10 kD and a DSvalue of about 0.4.

Another especially preferred protein coupled via above-mentioned amidelinkage to hydroxyalkyl starch, preferably hydroxyethyl starch, is IFNalpha. Therefore, the present invention also relates to a conjugate

wherein the N atom of the amide linkage is derived from an amino groupof IFN alpha and where HAS′ is preferably HES′ and even more preferablyhydroxyethyl starch having a molecular weight of about 18 kD and a DSvalue of about 0.8.

In the above described embodiment where an amino group of the protein isreacted with a reactive carboxy group of the polymer or polymerderivative, particularly preferred hydroxyethyl starches are, e.g.,hydroxyethyl starches having a mean molecular weight of about 10 kD anda DS of about 0.4 or hydroxyethyl starches having a mean molecularweight of about 18 kD and a DS of about 0.8. Also possible arehydroxyethyl starch having a mean molecular weight of about 10 kD and aDS of about 0.7 and hydroxyethyl starch having a mean molecular weightof about 18 kD and a DS of about 0.4 and hydroxyethyl starch having amean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 12 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 12 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 18 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 30 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 30 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

The reaction of the reactive polymer with the protein may be carried outby combining the reaction mixture of the preparation of the reactivepolymer, i.e. without isolation of the reactive polymer, comprising atleast 10, more preferably at least 30 and still more preferably at least50 percent by weight reactive polymer, with an aqueous solution of theprotein. Preferred aqueous solutions of the protein comprises of from0.05 to 10, more preferably of from 0.5 to 5 and especially preferablyof from 0.5 to 2 percent by weight protein at a preferred pH of from 5.0to 9.0, more preferably of from 6.0 to 9.0 and especially preferably offrom 7.5 to 8.5.

According to the present invention, it is also possible to purify thereactive polymer by at least one, preferably multiple precipitation withat least one suitable precipitation agent such as anhydrous ethanol,isopropanol and/or acetone to give a solid comprising at least 10, morepreferably at least 30 and still more preferably at least 50 percent byweight reactive polymer.

The purified reactive polymer may be added to the aqueous solution ofthe protein. It is also possible to add a solution of the purifiedreactive polymer to the aqueous solution of the protein.

According to a preferred embodiment of the present invention, thereaction of the reactive polymer with the protein to give an amidelinkage is carried out at a temperature of from 2 to 40° C., morepreferably of from 5 to 35° C. and especially of from 10 to 30° C. and apreferred pH of from 7.0 to 9.0, preferably of from 7.5 to 9.0 andespecially preferably of from 7.5 to 8.5, at a preferred reaction timeof from 0.1 to 12 h, more preferably of from 0.5 to 5 h, more preferablyof from 0.5 to 3 h, still more preferably of from 0.5 to 2 h andespecially preferably of from 0.5 to 1 h, the molar ratio of reactivepolymer ester:protein being preferably of from 1:1 to 70:1, morepreferably of from 5:1 to 50:1 and especially preferably of from 10:1 to50:1.

According to another embodiment of the present invention, the polymerwhich is selectively oxidized at its reducing end is reacted at theoxidized reducing end with an azolide such as carbonyldiimidazole orcarbonyl dibenzimidazole to give a polymer having a reactive carboxygroup. In the case of carbonyldiimidazole, a reactive polymer derivativeaccording to formula

results, wherein HAS′ is preferably HES′. The imidazolide resulting fromthe reaction of the polymer with the azolide may be preferentiallyreacted with an amino group of the protein to give an amide linkage.Also possible is a reaction, if present, with a hydroxy group of theprotein to give an ester linkage, or with a thio group of the protein togive a thioester linkage, or, if present, with a carboxy group of theprotein to give a —(C═O)—O—(C═O)— linkage.

In the above described embodiment where an azolide is used forintroducing the reactive carboxy group in the polymer or polymerderivative, particularly preferred hydroxyethyl starches are, e.g.,hydroxyethyl starches having a mean molecular weight of about 10 kD anda DS of about 0.4 or hydroxyethyl starch having a mean molecular weightof about 10 kD and a DS of about 0.7 or hydroxyethyl starch having amean molecular weight of about 18 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 30 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 30 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 50 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 50 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 12 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 12 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 18 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

According to another embodiment of the present invention, the polymerhaving a reactive carboxy group A resulting from the reaction of theselectively oxidized reducing end of the polymer with one of theabove-mentioned compounds, preferably with at least one of the acidicalcohols and/or at least one of the carbonic diester compounds, may belinked to the functional group Z of the protein via at least one linkercompound. In case a linker compound is used, said compound is an atleast bifunctional compound having at least one functional group F₁capable of being reacted with the functional group A of the polymerderivative, and at least one functional group F₂ being capable of beingreacted with the functional group Z of the protein or a functional groupF₂ being capable of being chemically modified to be reacted with thefunctional group Z of the protein. The chemical modification may be,e.g., a reaction of the functional group F₂ with a functional group F₃of a further linker compound or an oxidation or a reduction of asuitable functional group F₂. In case at least one linker compound isused, the reaction is not restricted to the amino group of the proteinbut, depending on the chemical nature of the functional groups of thelinker compound or linker compounds, may be used to form a linkage witheach suitable functional group of the protein, such as a carboxy group,a reactive carboxy group, an aldehyde group, a keto group, a thio group,an amino group or a hydroxy group. In case two linker compounds areused, a first linker compound is employed having at least one functionalgroup F₁ being capable of being reacted with the reactive carboxy groupA of the polymer, such as an amino group, a thio group, a hydroxy group,or a carboxy group. Moreover, the first linker compound has at least oneother functional group F₂ which is capable of being reacted with atleast one functional group F₃ of the second linker compound. As tofunctional group F₂, the following functional groups are to bementioned, among others:

-   -   C—C-double bonds or C—C-triple bonds or aromatic C—C-bonds;    -   the thio group or the hydroxy groups;    -   alkyl sulfonic acid hydrazide, aryl sulfonic acid hydrazide;    -   1,2-diols;    -   1,2-aminoalcohols;    -   1,2-amino-thioalcohols;    -   azides;    -   the amino group —NH₂ or derivatives of the amino groups        comprising the structure unit —NH— such as aminoalkyl groups,        aminoaryl group, aminoaralkyl groups, or alkarylaminogroups;    -   the hydroxylamino group —O—NH₂, or derivatives of the        hydroxylamino group comprising the structure unit —O—NH—, such        as hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxyalkarylamino groups;    -   alkoxyamino groups, aryloxyamino groups, aralkyloxyamino groups,        or alkaryloxyamino groups, each comprising the structure unit        —NH—O—;    -   residues having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,        -   —OH or —SH;        -   an alkoxy group, an aryloxy group, an aralkyloxy group, or            an alkaryloxy group;        -   an alkylthio group, an arylthio group, an aralkylthio group,            or an alkarylthio group;        -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an            aralkylcarbonyloxy group, an alkarylcarbonyloxy group;        -   activated esters such as esters of hydroxylamines having            imid structure such as N-hydroxysuccinimide or having a            structure unit O—N where N is part of a heteroaryl compound            or, with G=O and Q absent, such as aryloxy compounds with a            substituted aryl residue such as pentafluorophenyl,            paranitrophenyl or trichlorophenyl;    -   wherein Q is absent or NH or a heteroatom such as S or O;        -   —NH—NH₂, or —NH—NH—;        -   —NO₂;        -   the nitril group;        -   carbonyl groups such as the aldehyde group or the keto            group;        -   the carboxy group;        -   the —N═C═O group or the —N═C═S group;    -   vinyl halide groups such as the vinyl iodide or the vinyl        bromide group or triflate;        -   —C≡C—H;        -   —(C═NH₂Cl)—OAlkyl        -   groups —(C═O)—CH₂-Hal wherein Hal is Cl, Br, or I;        -   —CH═CH—SO₂—;        -   a disulfide group comprising the structure —S—S—;

-   -   the group

wherein F₃ is a group capable of forming a chemical linkage with one ofthe above-mentioned groups and is preferably selected from theabove-mentioned groups. Moreover, the second linker compound has atleast one functional group which is capable of being reacted with thefunctional group Z of the protein, which is, e.g., an amino group, athio group, a carboxy group, a reactive carboxy group, an aldehydegroup, a keto group, or a hydroxy group. In case one linking compound isused to covalently link the polymer and the protein, the polymer can bereacted with the linking compound and the resulting polymer derivativeis reacted with the protein, or the protein can be reacted with thelinking compound and the resulting protein derivative is reacted withthe polymer. In case two linking compounds L1 and L2 are used, it ispossible to react the polymer with L1, react the resulting polymerderivative with L2 and react the resulting polymer derivative with theprotein, or to react the protein with L2, react the resulting proteinderivative with L1 and react the resulting protein derivative with thepolymer. It is also possible to react the polymer with L1 and react theprotein with L2 and react the polymer derivative with the proteinderivative. Furthermore, it is possible to react L1 with L2, react theresulting compound with the polymer and the resulting polymer derivativewith the protein. Furthermore, it is possible to react L1 with L2, reactthe resulting compound with the protein and the resulting proteinderivative with the polymer.wherein F₃ is a group capable of forming a chemical linkage with one ofthe above-mentioned groups and is preferably selected from theabove-mentioned groups. Moreover, the second linker compound has atleast one functional group which is capable of being reacted with thefunctional group Z of the protein, which is, e.g., an amino group, athio group, a carboxy group, a reactive carboxy group, an aldehydegroup, a keto group, or a hydroxy group. In case one linking compound isused to covalently link the polymer and the protein, the polymer can bereacted with the linking compound and the resulting polymer derivativeis reacted with the protein, or the protein can be reacted with thelinking compound and the resulting protein derivative is reacted withthe polymer. In case two linking compounds L1 and L2 are used, it ispossible to react the polymer with L1, react the resulting polymerderivative with L2 and react the resulting polymer derivative with theprotein, or to react the protein with L2, react the resulting proteinderivative with L1 and react the resulting protein derivative with thepolymer. It is also possible to react the polymer with L1 and react theprotein with L2 and react the polymer derivative with the proteinderivative. Furthermore, it is possible to react L1 with L2, react theresulting compound with the polymer and the resulting polymer derivativewith the protein. Furthermore, it is possible to react L1 with L2, reactthe resulting compound with the protein and the resulting proteinderivative with the polymer.

In the above described embodiment where linker compound is used incombination with an acidic alcohol and/or an diester carbonate and/or anazolide, particularly preferred hydroxyethyl starches are, e.g.,hydroxyethyl starches having a mean molecular weight of about 10 kD anda DS of about 0.4 or hydroxyethyl starch having a mean molecular weightof about 10 kD and a DS of about 0.7 or hydroxyethyl starch having amean molecular weight of about 18 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 12 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 12 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 18 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 30 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 30 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 50 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

According to a second preferred embodiment of the present inventionregarding the introduction of a reactive carboxy group into the polymer,the reactive carboxy group is introduced into the polymer whose reducingend is not oxidized, by reacting at least one hydroxy group of thepolymer with a carbonic diester.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein A is a reactive carboxy group, andwherein A is introduced in the polymer whose reducing end is notoxidized, by reacting at least one hydroxy group of the polymer with atleast one carbonic diester carbonic diester R_(B)—O—(C═O)—O—R_(C),wherein R_(B) and R_(C) may be the same or different.

According to another embodiment of the present invention, the polymerwhose reducing end is not oxidized, is reacted at at least one hydroxygroup with an azolide such as carbonyldiimidazole,carbonyl-di-(1,2,4-triazole) or carbonyl dibenzimidazol to give apolymer having a reactive carboxy group.

As suitable carbonic diester compounds, compounds may be employed whosealcohol components are independently N-hydroxy succinimides such asN-hydroxy succinimide or Sulfo-N-hydroxy succinimide, suitablysubstituted phenols such as p-nitrophenol, o,p-dinitrophenol,o,o′-dinitrophenol, trichlorophenol such as 2,4,6-trichlorophenol or2,4,5-trichlorophenol, trifluorophenol such as 2,4,6-trifluorophenol or2,4,5-trifluorophenol, pentachlorophenol, pentafluorophenol, orhydroxyazoles such as hydroxy benzotriazole.

Especially preferred are symmetrical carbonic diester compounds, R_(B)and R_(C) thus being the same. The alcohol component of the carbonicdiester is preferably selected from the group consisting of N-hydroxysuccinimide, sulfonated N-hydroxy succinimide, N-hydroxy benzotriazole,and nitro- and halogen-substituted phenols. Among others, nitrophenol,dinitrophenol, trichlorophenol, trifluorophenol, pentachlorophenol, andpentafluorophenol are preferred. Especially preferred areN,N′-disuccinimidyl carbonate and Sulfo-N,N′-disuccinimidyl carbonate,with N,N′-disuccinimidyl carbonate being especially preferred.

Therefore, the present invention also relates to a hydroxyalkyl starchderivative and a method of producing same, preferably a hydroxyethylstarch derivative, wherein at least one hydroxy group, preferably atleast two hydroxy groups of said starch have been reacted with acarbonic diester compound to give the respective reactive ester.

According to a preferred embodiment of the present invention, thereaction of the polymer whose reducing end is not oxidized, with the atleast one carbonic diester compound is carried out at a temperature offrom 2 to 40° C., more preferably of from 10 to 30° C. and especially offrom 15 to 25° C. and at a preferred reaction time of from 0.5 to 5 h,more preferably of from 1 to 3 h, and especially preferably of from 2 to3 h.

According to another embodiment of the present invention, the polymerwhose reducing end is not oxidized, is reacted at at least one hydroxygroup with an azolide such as carbonyldiimidazole,carbonyl-di-(1,2,4-triazole) or carbonyl dibenzimidazol to give apolymer having a reactive carboxy group.

The molar ratio of carbonic diester and/or azolide, preferably carbonicdiester compound:polymer depends on the degree of substitution of thepolymer regarding the number of hydroxy groups reacted with carbonicdiester compound relative to the number of hydroxy groups present in thenon-reacted polymer.

According to one preferred embodiment of the present invention, themolar ratio of carbonic diester compound:polymer is in the range of from1:2 to 1:1000, more preferably of from 1:3 to 1:100 and especiallypreferably of from 1:10 to 1:50, to give a degree of substitution in therange of from 0.5 to 0.001, preferably of from 0.33 to 0.01 andespecially preferably of from 0.1 to 0.02. The degree of substitution isdetermined by UV-spectroscopy.

According to a preferred embodiment of the present invention, reactingthe polymer whose reducing end is not oxidized, with carbonic diester iscarried out in at least one aprotic solvent, particularly preferably inan anhydrous aprotic solvent having a water content of not more than 0.5percent by weight, preferably of not more than 0.1 percent by weight.Suitable solvents are, among others, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, dimethyl acetamide (DMA), dimethyl formamide (DMF) andmixtures of two or more thereof.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the reaction of the at least onehydroxy group of the polymer whose reducing end is not oxidised, withthe carbonic diester to give a reactive ester group A is carried out inan anhydrous aprotic polar solvent, the solvent preferably beingdimethyl acetamide, dimethyl formamide or a mixture thereof.

The reaction of the reactive polymer comprising at least one reactiveester group, preferably at least two reactive ester groups, with theprotein to give at least one amide linkage, preferably at least twoamide linkages, may be carried out by combining the reaction mixture ofthe preparation of the reactive polymer, i.e. without isolation of thereactive polymer, comprising at least 5, more preferably at least 10 andstill more preferably at least 15 percent by weight reactive polymer,with an aqueous solution of the protein. Preferred aqueous solutions ofthe protein comprises of from 0.05 to 10, more preferably of from 0.5 to5 and especially preferably of from 0.5 to 2 percent by weight proteinat a preferred pH of from 7.0 to 9, more preferably of from 7.5 to 9 andespecially preferably of from 7.5 to 8.5.

According to the present invention, it is also possible to purify thereactive polymer by at least one, preferably by multiple precipitationwith at least one suitable precipitation agent such as anhydrousethanol, isopropanol and/or acetone to give a solid comprising at least20, more preferably at least 50 and still more preferably at least 80percent by weight reactive polymer.

The purified reactive polymer may be added to the aqueous solution ofthe protein. It is also possible to add a solution of the purifiedreactive polymer to the aqueous solution of the protein.

According to a preferred embodiment of the present invention, thereaction of the reactive polymer with the protein to give at least one,preferably at least two amide linkages is carried out at a temperatureof from 2 to 40° C., more preferably of from 5 to 35° C. and especiallyof from 10 to 30° C. and a preferred pH of from 7.0 to 9.5, preferablyof from 7.5 to 9 and especially preferably of from 7.5 to 8.5, at apreferred reaction time of from 0.5 to 5 h, more preferably of from 0.5to 3 h and especially preferably of from 0.5 to 1 h, the molar ratio ofreactive polymer ester:protein being preferably of from 1:1 to 70:1,more preferably of from 5:1 to 50:1 and especially preferably of from10:1 to 50:1.

According to a preferred embodiment of the present invention, oligo- ormultiprotein-substituted polymers are obtained wherein the proteinmolecules are linked to the polymer via an amide linkage.

PDS is in the range of from 0.001 to 1, preferably from 0.005 to 0.5,more preferably from 0.005 to 0.2.

In the above described embodiment where at least one reactive carboxygroup is introduced in the polymer or polymer derivative by reactionwith at least one hydroxy group of the polymer or polymer derivative,particularly preferred hydroxyethyl starches are, e.g., hydroxyethylstarches having a mean molecular weight of about 10 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 10 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 18 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 12 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 12 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 18 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 30 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 30 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

According to another embodiment of the present invention, the polymerhaving a reactive carboxy group A resulting from the reaction of atleast one hydroxy group of the polymer with one of the above-mentionedcompounds, preferably with at least one of the carbonic diestercompounds, may be linked to the functional group Z of the protein via atleast one linker compound. In case a linker compound is used, saidcompound is an at least bifunctional compound having at least onefunctional group F₁ capable of being reacted with the functional group Aof the polymer derivative, and at least one functional group F₂ beingcapable of being reacted with the functional group Z of the protein or afunctional group F₂ being capable of being chemically modified to bereacted with the functional group Z of the protein. The chemicalmodification may be, e.g., a reaction of the functional group F₂ with afunctional group F₃ of a further linker compound or an oxidation or areduction of a suitable functional group F₂. In case at least one linkercompound is used, the reaction is not restricted to the amino group ofthe protein but, depending on the chemical nature of the functionalgroups of the linker compound or linker compounds, may be used to form alinkage with each suitable functional group of the protein, such as acarboxy group, a reactive carboxy group, an aldehyde group, a ketogroup, a thio group, an amino group or a hydroxy group. In case twolinker compounds are used, a first linker compound is employed having atleast one functional group F₁ being capable of being reacted with thereactive carboxy group A of the polymer, such as an amino group, a thiogroup, a hydroxy group, or a carboxy group. Moreover, the first linkercompound has at least one other functional group F₂ which is capable ofbeing reacted with at least one functional group F₃ of the second linkercompound. As to functional group F₂, the following functional groups areto be mentioned, among others:

-   -   C—C-double bonds or C—C-triple bonds or aromatic C—C-bonds;    -   the thio group or the hydroxy groups;    -   alkyl sulfonic acid hydrazide, aryl sulfonic acid hydrazide;    -   1,2-dioles;    -   1,2-aminoalcohols;    -   azides;    -   1,2-amino-thioalcohols;    -   the amino group —NH₂ or derivatives of the amino groups        comprising the structure unit —NH— such as aminoalkyl groups,        aminoaryl group, aminoaralkyl groups, or alkarylaminogroups;    -   the hydroxylamino group —O—NH₂, or derivatives of the        hydroxylamino group comprising the structure unit —O—NH—, such        as hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxyalkarylamino groups;    -   alkoxyamino groups, aryloxyamino groups, aralkyloxyamino groups,        or alkaryloxyamino groups, each comprising the structure unit        —NH—O—;    -   residues having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,        -   —OH or —SH;        -   an alkoxy group, an aryloxy group, an aralkyloxy group, or            an alkaryloxy group;        -   an alkylthio group, an arylthio group, an aralkylthio group,            or an alkarylthio group;        -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an            aralkylcarbonyloxy group, an alkarylcarbonyloxy group;        -   activated esters such as esters of hydroxylamines having            imid structure such as N-hydroxysuccinimide or having a            structure unit O—N where N is part of a heteroaryl compound            or, with G=O and Q absent, such as aryloxy compounds with a            substituted aryl residue such as pentafluorophenyl,            paranitrophenyl or trichlorophenyl;    -   wherein Q is absent or NH or a heteroatom such as S or O;        -   —NH—NH₂, or —NH—NH—;        -   —NO₂;        -   the nitril group;        -   carbonyl groups such as the aldehyde group or the keto            group;        -   the carboxy group;        -   the —N═C═O group or the —N═C═S group;    -   vinyl halide groups such as the vinyl iodide or the vinyl        bromide group or triflate;        -   —C≡C—H;        -   —(C═NH₂Cl)—OAlkyl        -   groups —(C═O)—CH₂-Hal wherein Hal is Cl, Br, or I;        -   —CH═CH—SO₂—;        -   a disulfide group comprising the structure —S—S—;

-   -   the group

wherein F₃ is a group capable of forming a chemical linkage with one ofthe above-mentioned groups and is preferably selected from theabove-mentioned groups. Moreover, the second linker compound has atleast one functional group which is capable of being reacted with thefunctional group Z of the protein, which is, e.g., an amino group, athio group, a carboxy group, a reactive carboxy group, an aldehydegroup, a keto group, or a hydroxy group. In case one linking compound isused to covalently link the polymer and the protein, the polymer can bereacted with the linking compound and the resulting polymer derivativeis reacted with the protein, or the protein can be reacted with thelinking compound and the resulting protein derivative is reacted withthe polymer. In case two linking compounds L1 and L2 are used, it ispossible to react the polymer with L1, react the resulting polymerderivative with L2 and react the resulting polymer derivative with theprotein, or to react the protein with L2, react the resulting proteinderivative with L1 and react the resulting protein derivative with thepolymer. It is also possible to react the polymer with L1 and react theprotein with L2 and react the polymer derivative with the proteinderivative. Furthermore, it is possible to react L1 with L2, react theresulting compound with the polymer and the resulting polymer derivativewith the protein. Furthermore, it is possible to react L1 with L2, reactthe resulting compound with the protein and the resulting proteinderivative with the polymer.

In the above described embodiment where a linker compound is used,particularly preferred hydroxyethyl starches are, e.g., hydroxyethylstarches having a mean molecular weight of about 10 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 10 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 18 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 12 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 12 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 18 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 30 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 30 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

According to a further especially preferred embodiment of the presentinvention, the functional group A to be reacted with the functionalgroup Z being an amino group is an aldehyde group, a keto group or ahemiacetal group. Therefore, the present invention also relates to amethod and a conjugate as described above, wherein the functional groupZ is an amino group and the functional group A of the polymer or thederivative thereof is an aldehyde group, a keto group or a hemiacetalgroup, wherein the protein is selected from the group consisting of IFNalpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII, factorVIII, and factor IX.

According to a particularly preferred embodiment, functional group Z andfunctional group A are reacted via a reductive amination reaction.

The reductive amination reaction according to the invention, wherein thepolymer or polymer derivative is covalently linked via at least onealdehyde group to at least one amino group of the protein by reductiveamination, is preferably carried out at a temperature of from 0 to 40°C., more preferably 0 to 37° C., more preferably of from 0 to 25° C., inparticular from 4 to 21° C., but especially preferably of from 0 to 21°C. The reaction time preferably ranges of from 0.5 to 72 h, morepreferably of from 2 to 48 h and especially preferably of from 4 to 7 h.As solvent for the reaction, an aqueous medium is preferred.

Thus, the present invention also relates to a method and a conjugate asdescribed above, wherein the reductive amination is carried out at atemperature of from 4 to 21° C., but especially preferably 0 to 21° C.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein reductive amination is carried outin an aqueous medium.

Thus, the present invention also relates to a method and conjugate asdescribed above, wherein the reductive amination is carried out at atemperature of from 4 to 21° C., but especially preferably 0 to 21° C.,in an aqueous medium.

The term “aqueous medium” as used in the context of the presentinvention relates to a solvent or a mixture of solvents comprising waterin the range of from at least 10% per weight, more preferably at least20% per weight, more preferably at least 30% per weight, more preferablyat least 40% per weight, more preferably at least 50% per weight, morepreferably at least 60% per weight, more preferably at least 70% perweight, more preferably at least 80% per weight, even more preferably atleast 90% per weight or up to 100% per weight, based on the weight ofthe solvents involved. The preferred reaction medium is water.

The pH value of the reaction medium is generally in the range of from 4to 9 or from 4 to 8 or from 4 to 7.3.

According to a preferred embodiment of the present invention, the pH atwhich the reductive amination reaction is carried out, is below 10,preferably below 7.5, preferably below 7.3, more preferably smaller orequal 7 and most preferably below 7, i.e. in the acidic range. Preferredranges are therefore of from 3 to below 7, more preferably of from 3.5to 6.5, still more preferably of from 4 to 6, still more preferably offrom 4.5 to 5.5 and especially preferably about 5.0, i.e. 4.6 or 4.7 or4.8 or 4.9 or 5.0. or 5.1 or 5.2 or 5.3 or 5.4. Preferred ranges, areamong others, 3 to 6.9 or 3 to 6.5 or 3 to 6 or 3 to 5.5 or 3 to 5 or 3to 4.5 or 3 to 4 or 3 to 3.5 or 3.5 to 6.9 or 3.5 to 6.5 or 3.5 to 6 or3.5 to 5.5 or 3.5 to 5 or 3.5 to 4.5 or 3.5 to 4 or 4 to 6.9 or 4 to 6.5or 4 to 6.0 or 4 to 5.5 or 4 to 5 or 4 to 4.5 or 4.5 to 6.9 or 4.5 to6.5 or 4.5 to 6 or 4.5 to 5.5 or 4.5 to 5 or 5 to 6.9 or 5 to 6.5 or 5to 6 or 5 to 5.5 or 5.5 to 6.9 or 5.5 to 6.5 or 5.5 to 6 or 6 to 6.9 or6 to 6.5 or 6.5 to 6.9.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the reductive amination is carriedout at a pH of 7 or less, more preferably at a pH of 6 or less.

Thus, the present invention also relates to a method and conjugate asdescribed above, wherein the reductive amination is carried out at atemperature of from 0 to 21° C., preferably 4 to 21° C. at a pH of 7.5or less, preferably 7 or less, preferably of 6 or less.

Hence, the present invention also relates to a method and conjugate asdescribed above, wherein the reductive amination is carried out in anaqueous medium at a pH of 7 or less, preferably of 6 or less.

Accordingly, the present invention also relates to a method andconjugate as described above, wherein the reductive amination is carriedout at a temperature of from 4 to 21° C. in an aqueous medium at a pH of7 or less, preferably of 6 or less.

The molar ratio of polymer derivative:protein used for the reaction ispreferably in the range of from 200:1 to 5:1, more preferably of from100:1 to 10:1 and especially preferably of from 75:1 to 20:1.

It was surprisingly found that it was possible, especially at thepreferred pH ranges given above, particularly at a pH below 7 andgreater or equal 4, to react the polymer derivative predominantly withthe amino group located at the N terminus of the protein. The term“predominantly” as used in the context of the present invention relatesto an embodiment where at least 80%, preferably at least 85% of theN-terminal amino groups available are reacted via reductive amination.It is also possible to react at least 90% or at least 95% or at least96% or at least 97% or at least 98% or at least 99% of the N-terminalamino groups available. Although coupling to amino groups other than theN-terminal amino group could not be ruled out completely, it is believedthat coupling via reductive amination according to the present inventionat a pH of below 7, preferably below 6, took place essentiallyselectively at the N-terminal amino group. In particular, these reactionconditions are preferred for proteins which are stable at theseconditions. Should a protein e.g. be acid labile, such asalpha1-antitrypsin, then it is preferred to chose appropriate reactionconditions, in particular a pH from lower than 7.5 to greater than 5.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the protein comprises theN-terminal amino group and at least one further amino group, saidconjugate comprises the polymer being predominantly coupled to theN-terminal amino group.

According to an especially preferred embodiment, the present inventionrelates to a method of linking aldehyde or keto or hemiacetalfunctionalized hydroxyalkyl starch or an aldehyde or keto or hemiacetalfunctionalized hydroxyalkyl starch derivative predominantly to theN-terminal amino group of a protein, said method comprising subjectingsaid hydroxyalkyl starch or derivative thereof to a reductive aminationreaction, at a pH of 7 or less, preferably at a pH of 6 or less, saidreductive amination reaction being carried out preferably in an aqueousmedium.

According to the present invention, aldehyde functionalized hydroxyalkylstarch or an aldehyde functionalized hydroxyalkyl starch derivative ispreferred.

According to a still further preferred embodiment, the present inventionrelates to a method of linking aldehyde or keto or hemiacetalfunctionalized hydroxyethyl starch or an aldehyde or keto or hemiacetalfunctionalized hydroxyethyl starch derivative selectively to theN-terminal amino group of a protein, said method comprising subjectingsaid hydroxyalkyl starch or derivative thereof to a reductive aminationreaction, at a pH of 7 or less, preferably at a pH of 6 or less, saidreductive amination reaction being carried out preferably in an aqueousmedium, the hydroxyethyl starch employed preferably being hydroxyethylstarch having a mean molecular weight of about 10 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 10 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 12 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 12 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 18 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 18 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 30 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 30 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 50 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 50 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

The reaction of the polymer derivative and the protein between thealdehyde group or keto group or hemiacetal group and the amino group isa reductive amination wherein a Schiff's base is produced. Subsequentlyafter the reaction, this base may be reduced by at least one reductiveagent to give a stable linkage between the polymer derivative and theprotein. It is also possible to carry out the reaction in the presenceof at least one reductive agent. According to a preferred embodiment,the reductive amination reaction is carried out in the presence of atleast one reductive agent.

Preferred reductive agents are sodium borohydride, sodiumcyanoborohydride, organic borane complex compounds such as a4-(dimethylamin)pyridine borane complex, N-ethyldiisopropylamine boranecomplex, N-ethylmorpholine borane complex, N-methylmorpholine boranecomplex, N-phenylmorpholine borane complex, lutidine borane complex,triethylamine borane complex, or trimethylamine borane complex.Particularly preferred is sodium cyanoborohydride.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the reductive amination is carriedout in the presence of NaCNBH₃.

Hence, the present invention also relates to a method and conjugate asdescribed above, wherein the reductive amination is carried out in anaqueous medium at a pH of 7 or less, preferably of 6 or less in thepresence of reductive agent, preferably NaCNBH₃.

Accordingly, the present invention also relates to a method andconjugate as described above, wherein the reductive amination is carriedout at a temperature of from 4 to 21° C. in an aqueous medium at a pH of7 or less, preferably of 6 or less in the presence of reductive agent,preferably NaCNBH₃.

The molar ratio of polymer derivative:protein used for the reaction ispreferably in the range of from 200:1 to 10:1 more preferably of from100:1 to 10:1 and especially preferably of from 75:1 to 20:1.

Therefore, the present invention also relates to a method of producing aconjugate, said method comprising reacting a polymer or a polymerderivative comprising an aldehyde group in an aqueous medium with anamino group of the protein in the presence of a reductive agent, saidreductive agent preferably being NaCNBH₃.

According to the first preferred embodiment of the present invention,according to which the polymer comprises at least two aldehyde groupswhich are introducing in the polymer by a ring-opening oxidationreaction, the polymer preferably comprises at least one structureaccording to formula

According to this embodiment of the present invention, each oxidationagent or combination of oxidation agents may be employed which iscapable of oxidizing at least one saccharide ring of the polymer to givean opened saccharide ring having at least one, preferably at least twoaldehyde groups. This reaction is illustrated by the following reactionscheme which shows a saccharide ring of the polymer which is oxidized togive an opened ring having two aldehyde groups:

Suitable oxidating agents are, among others, periodates such as alkalinemetal periodates or mixtures of two or more thereof, with sodiumperiodate and potassium periodate being preferred.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is subjected to aring-opening oxidation reaction using a periodate to give a polymerderivative having at least one, preferably at least two aldehyde groups.

For this oxidation reaction, the polymer may be employed with itsreducing end either in the oxidized or in the non-oxidized form, thenon-oxidized form being preferred.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is employed with itsreducing end in the non-oxidized form.

The reaction temperature is in a preferred range of from 0 to 40° C.,more preferably of from 0 to 25° C. and especially preferably of from 0to 5° C. The reaction time is in a preferred range of from 1 min to 5 hand especially preferably of from 10 min to 4 h. Depending on thedesired degree of oxidiation, i.e. the number of aldehyde groupsresulting from the oxidation reaction, the molar ratio ofperiodate:polymer may be appropriately chosen.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the ring-opening oxidationreaction is carried out at a temperature of from 0 to 5° C.

The oxidation reaction of the polymer with periodate is preferablycarried out in an aqueous medium, most preferably in water.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the ring-opening oxidationreaction is carried out in an aqueous medium. The suitable pH value ofthe reaction mixture may be adjusted by adding at least one suitablebuffer. Among the preferred buffers, sodium acetate buffer, phosphate orborate buffers may be mentioned.

The hydroxyethyl starch subjected to said ring-opening oxidationreaction is preferably hydroxyethyl starch having a mean molecularweight of about 10 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 10 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 12 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 12 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 18 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 18 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 30 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 30 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 50 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 50 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

The resulting polymer derivative may be purified from the reactionmixture by at least one suitable method. If necessary, the polymerderivative may be precipitated prior to the isolation by at least onesuitable method.

If the polymer derivative is precipitated first, it is possible, e.g.,to contact the reaction mixture with at least one solvent or solventmixture other than the solvent or solvent mixture present in thereaction mixture at suitable temperatures. According to a particularlypreferred embodiment of the present invention where an aqueous medium,preferably water is used as solvent, the reaction mixture is contactedwith 2-propanol or with am mixture of acetone and ethanol, preferably a1:1 mixture (v/v), indicating equal volumes of said compounds, at atemperature, preferably in the range of from −20 to +50° C. andespecially preferably in the range of from −20 to 25° C.

Isolation of the polymer derivative may be carried out by a suitableprocess which may comprise one or more steps. According to a preferredembodiment of the present invention, the polymer derivative is firstseparated off the reaction mixture or the mixture of the reactionmixture with, e.g., aqueous 2-propanol mixture, by a suitable methodsuch as centrifugation or filtration. In a second step, the separatedpolymer derivative may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation. According to an evenmore preferred embodiment, the separated polymer derivative is firstdialysed, preferably against water, and then lyophilized until thesolvent content of the reaction product is sufficiently low according tothe desired specifications of the product. Lyophilisation may be carriedout at temperature of from 20 to 35° C., preferably of from 20 to 30° C.

According to a preferred embodiment, the oxidized polymer resulting fromthe oxidation reaction is purified using at least one suitable methodsuch as ultrafiltration and/or dialysis in order to, e.g., removeundesirable low molecular weight salts and polymer components, therebyalso offering a means of controlling the molecular weight range ofoxidized polymer.

The oxidized polymer can be used directly for the reaction with theprotein or is suitably recovered in a first step, e.g. bylyophilization, and redissolved in water for conjugation to the proteinin a second step. As to the coupling of at least one amino group of theprotein with at least one aldehyde group of the polymer by reductiveamination, reference is made to the detailed disclosure above concerningthe specific reaction parameters of the reductive amination reactionsuch as pH or temperature. According to especially preferred embodimentsof the present invention, the reductive amination is preferably carriedout at a temperature of from 0 to 5° C. such as about 4° C. at a pH ofabout 4.5 to 5.5 such as about 5.0 and for a reaction time of about 20to 30 h such as about 24 h.

According to the second preferred embodiment, the polymer is reactedwith an at least bifunctional compound comprising at least onefunctional group M capable of being reacted with the polymer and atleast one functional group Q which is an aldehyde group, a keto group ora hemiacetal group and which is reacted with an amino group of theprotein by reductive amination.

It is preferred to employ a compound having, apart from the aldehydegroup or keto group or hemiacetal group, at least one carboxy group orat least one reactive carboxy group, preferably one carboxy group or onereactive carboxy group. The aldehyde group or keto group or hemiacetalgroup and the carboxy group or the reactive carboxy group may beseparated by any suitable spacer. Among others, the spacer may be anoptionally substituted, linear, branched and/or cyclic hydrocarbonresidue. Generally, the hydrocarbon residue has from 1 to 60, preferablyfrom 1 to 40, more preferably from 1 to 20, more preferably from 2 to10, more preferably from 2 to 6 and especially preferably from 2 to 4carbon atoms. If heteroatoms are present, the separating group comprisesgenerally from 1 to 20, preferably from 1 to 8 and especially preferablyfrom 1 to 4 heteroatoms. The hydrocarbon residue may comprise anoptionally branched alkyl chain or an aryl group or a cycloalkyl grouphaving, e.g., from 5 to 7 carbon atoms, or be an aralkyl group, analkaryl group where the alkyl part may be a linear and/or cyclic alkylgroup.

According to a preferred embodiment, the hydrocarbon residue is an alkylgroup having 2 to 6 and preferably 2 to 4 carbon atoms. It is alsopossible that no carbon atom is present between the aldehyd or ketogroup and the carboxy group. Alternatively, the hydrocarbon residue canbe a substituted or unsubstituted cyclic hydrocarbon group having 3 to11 carbon atoms, preferably, 3 to 6 or 3 to 5 carbon atoms. When thecyclic hydrocarbon group is substituted, the substituent can be selectedfrom the group consisting of substituted or unsubstituted amino oralkoxy groups. If present, the number of substituents is preferably 1 to3. Further, the alkyl and/or cyclic hydrocarbon group can contain one ormore heteroatoms, such as O or S, in particular O. In this case,preferably 1 to 3, in particular 1 or 2 heteroatoms are present.Preferred compounds in this context are selected from the followinggroup of compounds.

According to an even more preferred embodiment, the hydrocarbon residueis an aryl residue having 5 to 7 and preferably 6 carbon atoms. Mostpreferably, the hydrocarbon residue is the benzene residue. According tothis preferred embodiment, the carboxy group and the aldehyde group maybe located at the benzene ring in 1,4-position, 1,3-position or1,2-position, the 1,4-position being preferred.

As reactive carboxy group, a reactive ester, isothiocyanates orisocyanate may be mentioned. Preferred reactive esters are derived fromN-hydroxy succinimides such as N-hydroxy succinimide or Sulfo-N-hydroxysuccinimide, suitably substituted phenols such as p-nitrophenol,o,p-dinitrophenol, o,o′-dinitrophenol, trichlorophenol such as2,4,6-trichlorophenol or 2,4,5-trichlorophenol, trifluorophenol such as2,4,6-trifluorophenol or 2,4,5-trifluorophenol, pentachlorophenol,pentafluorophenol, or hydroxyazoles such as hydroxy benzotriazole.Especially preferred are N-hydroxy succinimides, with N-hydroxysuccinimide and Sulfo-N-hydroxy succinimide being especially preferred.All alcohols may be employed alone or as suitable combination of two ormore thereof. As reactive esters, pentafluorophenyl ester and N-hydroxysuccinimide ester are especially preferred.

Specific examples of the at least bifunctional compound comprising acarboxy group which may be reacted to obtain a reactive carboxy groupare the compounds 1 to 11 of the list hereinabove. In this context, theterm “carboxy group” also relates to a lacton and an internal anhydrideof a dicarboxylic acid compound.

Thus, according to a preferred embodiment, the present invention relatesto a method and a conjugate as described above, wherein the polymer isreacted with formylbenzoic acid.

According to another preferred embodiment, the present invention relatesto a method and a conjugate as described above, wherein the polymer isreacted with formylbenzoic acid pentafluorophenyl ester.

According to yet another preferred embodiment, the present inventionrelates to a method and a conjugate as described above, wherein thepolymer is reacted with formylbenzoic acid N-hydroxysuccinimide ester.

According to yet another embodiment, the present invention relates to amethod and a conjugate as described above, wherein the polymer isreacted with 4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid.

The hydroxyethyl starch subjected to the reaction with the compoundcomprising M, M preferably being a carboxy group or a reactive carboxygroup and Q being an aldehyde group or a keto group or a hemiacetalgroup, is most preferably hydroxyethyl starch having a mean molecularweight of about 10 kD and a DS of about 0.7. Also possible arehydroxyethyl starches having a mean molecular weight of about 10 kD anda DS of about 0.4 or hydroxyethyl starch having a mean molecular weightof about 12 kD and a DS of about 0.4 or hydroxyethyl starch having amean molecular weight of about 12 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 18 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 18 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 30 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 30 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 50 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 50 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

Particularly preferably, the hydroxyalkyl starch and even morepreferably the hydroxyethyl starch is employed with its reducing end inthe oxidized form.

The resulting polymer derivative with the aldehyde group or the ketogroup or the hemiacetal group is subsequently reacted with an aminogroup of the protein via reductive amination. As to the coupling of atleast one amino group of the protein with at least one aldehyde group orketo group or hemiacetal group of the polymer by reductive amination,reference is made to the detailed disclosure above concerning thespecific reaction parameters of the reductive amination reaction such aspH or temperature. According to an especially preferred embodiment ofthe present invention, the reaction with the amino group of the proteinis preferably carried out at a temperature of from 0 to 40° C., morepreferably of from 0 to 25° C. and especially preferably of from 4 to21° C. The reaction time preferably ranges of from 30 min to 72 h, morepreferably of from 2 to 48 h and especially preferably of from 4 h to 17h. As solvent for the reaction, an aqueous medium is preferred. The pHvalue of the reaction medium is preferably in the range of from 4 to 9,more preferably of from 4 to 8 and especially preferably of from 4.5 to5.5.

According to the third preferred embodiment, the polymer is reacted atits optionally oxidized reducing end with an at least bifunctionalcompound comprising an amino group M and a functional group Q, whereinsaid amino group M is reacted with the optionally oxidized reducing endof the polymer and wherein the functional group Q is chemically modifiedto give an aldehyde functionalized polymer derivative which is reactedwith an amino group of the protein by reductive amination.

As to functional group Q, the following functional groups are to bementioned, among others:

-   -   C—C-double bonds or C—C-triple bonds or aromatic C—C-bonds;    -   the thio group or the hydroxy groups;    -   alkyl sulfonic acid hydrazide, aryl sulfonic acid hydrazide;    -   1,2-dioles;        -   1,2 amino-thioalcohols;        -   azides;    -   1,2-aminoalcohols;    -   the amino group —NH₂ or derivatives of the amino groups        comprising the structure unit —NH— such as aminoalkyl groups,        aminoaryl group, aminoaralkyl groups, or alkarylaminogroups;    -   the hydroxylamino group —O—NH₂, or derivatives of the        hydroxylamino group comprising the structure unit —O—NH—, such        as hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxalalkarylamino groups;    -   alkoxyamino groups, aryloxyamino groups, aralkyloxyamino groups,        or alkaryloxyamino groups, each comprising the structure unit        —NH—O—;    -   residues having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,        -   —OH or —SH;        -   an alkoxy group, an aryloxy group, an aralkyloxy group, or            an alkaryloxy group;        -   an alkylthio group, an arylthio group, an aralkylthio group,            or an alkarylthio group;        -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an            aralkylcarbonyloxy group, an alkarylcarbonyloxy group;        -   activated esters such as esters of hydroxylamines having            imid structure such as N-hydroxysuccinimide or having a            structure unit O—N where N is part of a heteroaryl compound            or, with G=O and Q absent, such as aryloxy compounds with a            substituted aryl residue such as pentafluorophenyl,            paranitrophenyl or trichlorophenyl;    -   wherein Q is absent or NH or a heteroatom such as S or O;        -   —NH—NH₂, or —NH—NH—;        -   —NO₂;        -   the nitril group;        -   carbonyl groups such as the aldehyde group or the keto            group;        -   the carboxy group;        -   the —N═C═O group or the —N═C═S group;    -   vinyl halide groups such as the vinyl iodide or the vinyl        bromide group or triflate;        -   —C≡C—H;        -   —(C═NH₂Cl)—OAlkyl        -   groups —(C═O)—CH₂-Hal wherein Hal is Cl, Br, or I;        -   —CH═CH—SO₂—;        -   a disulfide group comprising the structure —S—S—;

-   -   the group

According to a preferred embodiment of the present invention, the term“functional group Q” relates to a functional group Q which comprises thechemical structure —NH—.

According to one preferred embodiment of the present invention, thefunctional group M is a group having the structure R′—NH— where R′ ishydrogen or a alkyl, cycloalkyl, aryl, aralkyl, arylcycloalkyl, alkarylor cycloalkylaryl residue where the cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl or cycloalkylaryl residue may be linked directlyto the NH group or, according to another embodiment, may be linked by anoxygen bridge to the NH group. The alkyl, cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl, or cycloalkylaryl residues may be suitablysubstituted. As preferred substituents, halogenes such as F, Cl or Brmay be mentioned. Especially preferred residues R′ are hydrogen, alkyland alkoxy groups, and even more preferred are hydrogen andunsubstituted alkyl and alkoxy groups.

Among the alkyl and alkoxy groups, groups with 1, 2, 3, 4, 5, or 6 Catoms are preferred. More preferred are methyl, ethyl, propyl,isopropyl, methoxy, ethoxy, propoxy, and isopropoxy groups. Especiallypreferred are methyl, ethyl, methoxy, ethoxy, and particular preferenceis given to methyl or methoxy.

According to another embodiment of the present invention, the functionalgroup M has the structure R′—NH—R″— where R″ preferably comprises thestructure unit —NH— and/or the structure unit —(C=G)- where G is O or S,and/or the structure unit —SO₂—. Specific examples for the functionalgroup R″ are

where, if G is present twice, it is independently O or S.

Therefore, the present invention also relates to a method and aconjugate as mentioned above wherein the functional group M is selectedfrom the group consisting of

wherein G is O or S and, if present twice, independently O or S, and R′is methyl.

According to a particularly preferred embodiment of the presentinvention, the functional group M is an amino group —NH₂.

The term “amino group Q” relates to a functional group Q which comprisesthe chemical structure —NH—.

According to a preferred embodiment of the present invention, thefunctional group Q is a group having the structure R′—NH— where R′ ishydrogen or a alkyl, cycloalkyl, aryl, aralkyl, arylcycloalkyl, alkarylor cycloalkylaryl residue where the cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl or cycloalkylaryl residue may be linked directlyto the NH group or, according to another embodiment, may be linked by anoxygen bridge to the NH group. The alkyl, cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl, or cycloalkylaryl residues may be suitablysubstituted. As preferred substituents, halogenes such as F, Cl or Brmay be mentioned. Especially preferred residues R′ are hydrogen, alkyland alkoxy groups, and even more preferred are hydrogen andunsubstituted alkyl and alkoxy groups.

Among the alkyl and alkoxy groups, groups with 1, 2, 3, 4, 5, or 6 Catoms are preferred. More preferred are methyl, ethyl, propyl,isopropyl, methoxy, ethoxy, propoxy, and isopropoxy groups. Especiallypreferred are methyl, ethyl, methoxy, ethoxy, and particular preferenceis given to methyl or methoxy.

According to another embodiment of the present invention, the functionalgroup Q has the structure R′—NH—R″— where R″ preferably comprises thestructure unit —NH— and/or the structure unit —(C=G)- where G is O or S,and/or the structure unit —SO₂—. According to more preferredembodiments, the functional group R″ is selected from the groupconsisting of

where, if G is present twice, it is independently O or S.

Therefore, the present invention also relates to a method and aconjugate as mentioned above wherein the functional group Q is selectedfrom the group consisting of

wherein G is O or S and, if present twice, independently O or S, and R′is methyl.

According to a particularly preferred embodiment of the presentinvention, the functional group Q is an amino group —NH₂.

According to a still further preferred embodiment of the presentinvention, both M and Q comprise an amino group —NH—. According to aparticularly preferred embodiment, both M and Q are an amino group —NH₂.

According to a preferred embodiment of the present invention, thecompound comprising M and Q is a homobifunctional compound, morepreferably a homobifunctional compound comprising, as functional groupsM and Q, most preferably the amino group —NH₂, or according to otherembodiments, the hydroxylamino group —O—NH₂ or the group

with G preferably being O. Specific examples for these compoundscomprising M and Q are

The hydroxyethyl starch subjected to the reaction with the compoundcomprising M, M preferably being an amino group —NH— and more preferablybeing an amino group —NH₂, still more preferably both M and Q comprisingan amino group —NH— and particularly preferably both M and Q comprisingan amino group —NH₂, is preferably hydroxyethyl starch having a meanmolecular weight of about 10 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 10 kD and a DS of about0.7. Also possible are or hydroxyethyl starches having mean molecularweight of about 12 kD and a DS of about 0.4 or hydroxyethyl starchhaving a mean molecular weight of about 12 kD and a DS of about 0.7 orhydroxyethyl starch having a mean molecular weight of about 18 kD and aDS of about 0.4 or hydroxyethyl starch having a mean molecular weight ofabout 18 kD and a DS of about 0.7 or hydroxyethyl starch having a meanmolecular weight of about 30 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 30 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 50 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 50 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

In case both M and Q are an amino group —NH₂, M and Q may be separatedby any suitable spacer. Among others, the spacer may be an optionallysubstituted, linear, branched and/or cyclic hydrocarbon residue.Generally, the hydrocarbon residue has from 1 to 60, preferably from 1to 40, more preferably from 1 to 20, more preferably from 2 to 10, morepreferably from 2 to 6 and especially preferably from 2 to 4 carbonatoms. If heteroatoms are present, the separating group comprisesgenerally from 1 to 20, preferably from 1 to 8 and especially preferablyfrom 1 to 4 heteroatoms. The hydrocarbon residue may comprise anoptionally branched alkyl chain or an aryl group or a cycloalkyl grouphaving, e.g., from 5 to 7 carbon atoms, or be an aralkyl group, analkaryl group where the alkyl part may be a linear and/or cyclic alkylgroup. According to an even more preferred embodiment, the hydrocarbonresidue is an alkyl chain of from 1 to 20, preferably from 2 to 10, morepreferably from 2 to 6, and especially preferably from 2 to 4 carbonatoms.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is reacted with1,4-diaminobutane, 1,3-diaminopropane or 1,2-diaminoethane to give apolymer derivative.

According to a first alternative, the functional group M being an aminogroup NH₂ is reacted with the oxidized reducing end of the polymerresulting in an amido group linking the polymer and the compoundcomprising M and Q.

According to a second alternative, the functional group M being an aminogroup NH₂ is reacted with the non-oxidized reducing end of the polymervia reductive amination resulting in an imino group which issubsequently preferably hydrogenated to give a amino group, the iminogroup and the amino group, respectively, linking the polymer and thecompound comprising M and Q. In this case, it is possible that thefunctional group Q is an amino group. In case that the resulting polymerderivative shall be subjected to a subsequent reaction with an at leastbifunctional compound via a carboxy group or a reactive carboxy group,as described hereinunder, or another group of an at least bifunctionalcompound which is to be reacted with an amino group, it is preferredthat the compound comprising M and Q is a primary amine whichcontains—as functional group—only one amino group. In this specificcase, although the compound contains only one functional group, it isregarded as bifunctional compound comprising M and Q wherein M is theamino group contained in the compound subjected to the reductiveamination with the reducing end of the polymer, and wherein Q is thesecondary amino group resulting from the reductive amination andsubsequent hydrogenation.

According to a third alternative, the non-oxidized reducing end of thepolymer is reacted with ammonia via reductive amination resulting in aterminal imino group of the polymer which is subsequently preferablyhydrogenated to give a terminal amino group of the polymer and thus aterminal primary amino group. In this specific case, ammonia is regardedas bifunctional compound comprising M and Q wherein M is NH₂ comprisedin the ammonia employed, and wherein Q is the primary amino groupresulting from reductive amination and subsequent hydrogenation.

The reaction of the at least bifunctional compound comprising M and Qwith the polymer is preferably carried out at a temperature of from 0 to100° C., more preferably of from 4 to 80° C. and especially preferablyof from 20 to 80° C.; the reaction time preferably ranges of from 4 h to7 d, more preferably of from 10 h to 5 d and especially preferably offrom 17 to 4 h. The molar ratio of at least bifunctionalcompound:polymer is preferably in the range of from 10 to 200, speciallyfrom 50 to 100.

As solvent for the reaction of the at least bifunctional compound withthe polymer, at least one aprotic solvent, particularly preferably ananhydrous aprotic solvent having a water content of not more than 0.5percent by weight, preferably of not more than 0.1 percent by weight ispreferred. Suitable solvents are, among others, dimethyl sulfoxide(DMSO), N-methyl pyrrolidone, dimethyl acetamide (DMA), dimethylformamide (DMF) and mixtures of two or more thereof.

As solvent for the reaction of the at least bifunctional compound withthe polymer, also an aqueous medium may be used.

According to a preferred embodiment, the polymer derivative comprisingthe polymer and the at least bifunctional compound is chemicallymodified at the free functional group Q to give a polymer derivativecomprising an aldehyde group or keto group or hemiacetal group.According to this embodiment, it is preferred to react the polymerderivative with at least one at least bifunctional compound whichcomprises a functional group capable of being reacted with thefunctional group Q and an aldehyde group or keto group or hemiacetalgroup.

As at least bifunctional compound, each compound is suitable which hasan aldehyde group or keto group or hemiacetal group and at least onefunctional group which is capable of forming a linkage with thefunctional group Q of the polymer derivative. The at least onefunctional group is selected from the same pool of functional groups asQ and is chosen to be able to be reacted with Q. In the preferred casethat Q is an amino group —NH₂, it is preferred to employ a compoundhaving, apart from the aldehyde group or keto group or hemiacetal group,at least one carboxy group or at least one reactive carboxy group,preferably one carboxy group or one reactive carboxy group. The aldehydegroup group or keto group or hemiacetal group and the carboxy group orthe reactive carboxy group may be separated by any suitable spacer.Among others, the spacer may be an optionally substituted, linear,branched and/or cyclic hydrocarbon residue. Generally, the hydrocarbonresidue has from 1 to 60, preferably from 1 to 40, more preferably from1 to 20, more preferably from 2 to 10, more preferably from 2 to 6 andespecially preferably from 2 to 4 carbon atoms. If heteroatoms arepresent, the separating group comprises generally from 1 to 20,preferably from 1 to 8 and especially preferably from 1 to 4heteroatoms. The hydrocarbon residue may comprise an optionally branchedalkyl chain or an aryl group or a cycloalkyl group having, e.g., from 5to 7 carbon atoms, or be an aralkyl group, an alkaryl group where thealkyl part may be a linear and/or cyclic alkyl group.

According to a preferred embodiment, the hydrocarbon residue is an alkylgroup having 2 to 6 and preferably 2 to 4 carbon atoms. It is alsopossible that no carbon atom is present between the aldehyd or ketogroup and the carboxy group. Alternatively, the hydrocarbon residue canbe a substituted or unsubstituted cyclic hydrocarbon group having 3 to11 carbon atoms, preferably, 3 to 6 or 3 to 5 carbon atoms. When thecyclic hydrocarbon group is substituted, the substituent can be selectedfrom the group consisting of substituted or unsubstituted amino oralkoxy groups. If present, the number of substituents is preferably 1 to3. Further, the alkyl and/or cyclic hydrocarbon group can contain one ormore heteroatoms, such as O or S, in particular O. In this case,preferably 1 to 3, in particular 1 or 2 heteroatoms are present.Preferred compounds in this context are selected from the followinggroup of compounds.

According to an even more preferred embodiment, the hydrocarbon residueis an aryl residue having 5 to 7 and preferably 6 carbon atoms. Mostpreferably, the hydrocarbon residue is the benzene residue. According tothis preferred embodiment, the carboxy group and the aldehyde group maybe located at the benzene ring in 1,4-position, 1,3-position or1,2-position, the 1,4-position being preferred.

As reactive carboxy group, a reactive ester, isothiocyanates orisocyanate may be mentioned. Preferred reactive esters are derived fromN-hydroxy succinimides such as N-hydroxy succinimide or Sulfo-N-hydroxysuccinimide, suitably substituted phenols such as p-nitrophenol,o,p-dinitrophenol, o,o′-dinitrophenol, trichlorophenol such as2,4,6-trichlorophenol or 2,4,5-trichlorophenol, trifluorophenol such as2,4,6-trifluorophenol or 2,4,5-trifluorophenol, pentachlorophenol,pentafluorophenol, or hydroxyazoles such as hydroxy benzotriazole.Especially preferred are N-hydroxy succinimides, with N-hydroxysuccinimide and Sulfo-N-hydroxy succinimide being especially preferred.All alcohols may be employed alone or as suitable combination of two ormore thereof. As reactive esters, pentafluorophenyl ester and N-hydroxysuccinimide ester are especially preferred.

According to a specific embodiment, the functional group which iscapable of forming a chemical linkage with the functional group Q, Qpreferably being NH₂ or a derivative of the amino group comprising thestructure unit —NH— such as aminoalkyl groups, aminoaryl group,aminoaralkyl groups, or alkarylamino groups, in particular being NH₂, isa reactive carboxy group.

In this case, the functional group which is capable of forming achemical linkage with the functional group Q and which is a carboxygroup, is suitably reacted to obtain a reactive carboxy group asdescribed hereinabove. Therefore, it is preferred to subject the atleast one at least bifunctional compound which comprises a carboxy groupand an aldehyde group or keto group or hemiacetal group, to a reactionwherein the carboxy group is transformed into a reactive carboxy group,and the resulting at least bifunctional compound is purified and reactedwith functional group Q of the polymer derivative.

Specific examples of the at least bifunctional compound comprising acarboxy group which may be reacted to obtain a reactive carboxy groupare the compounds 1 to 11 of the list hereinabove. In this context, theterm “carboxy group” also relates to a lacton and an internal anhydrideof a dicarboxylic acid compound.

Thus, according to a preferred embodiment, the present invention relatesto a method and a conjugate as described above, wherein the polymerderivative comprising Q, Q being an amino group —NH₂, is further reactedwith formylbenzoic acid.

According to another embodiment, the present invention relates to amethod and a conjugate as described above, wherein the polymerderivative comprising Q, Q being an amino group, is further reacted withformylbenzoic acid pentafluorophenyl ester.

According to yet another embodiment, the present invention relates to amethod and a conjugate as described above, wherein the polymerderivative comprising Q, Q being an amino group, is further reacted withformylbenzoic acid N-hydroxysuccinimide ester.

According to yet another embodiment, the present invention relates to amethod and a conjugate as described above, wherein the polymerderivative comprising Q, Q being an amino group, is further reacted with4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid.

According to another preferred embodiment, the present invention relatesto a method and a conjugate as described above, wherein the polymerderivative comprising Q, Q being an amino group —NH₂, is further reactedwith a bifunctional compound which is a biocompatible compound selectedfrom the group consisting of alpha-keto carboxylic acids, sialic acidsor derivatives thereof and pyridoxal phosphate.

As regards alpha-keto carboxylic acids, those are preferably alpha-ketocarboxylic acids derived from amino acids and can in most instances alsobe found in the human body. Preferred alpha-keto carboxylic acidsderived from amino acids are selected from the group consisting ofketo-valine, keto-leucine, keto-isoleucine and keto-alanine. The carboxygroup of the alpha-keto carboxylic acids is reacted with group Q of thepolymer being an amino group. Therewith an amido group is formed. Theremaining free keto group of the alpha-keto carboxylic acid may then bereacted with a functional group of the protein, in particular an aminogroup. Therewith an imino group is formed which may be hydrogenated.

Accordingly, the present invention relates to a method and a conjugateas described above, wherein the polymer derivative comprising Q, Q beingan amino group, is further reacted with an alpha-keto carboxylic acid.

As regards sialic acids or derivatives thereof those are preferablybiocompatible, in particular they are sugars found in the human body,which are N- and/or O-acetylated. In a preferred embodiment, theneuramic acids or sialic acids are N-acetyl neuramic acids. Thesecompounds show a desired rigidity because of the pyranose structure inorder to fulfill the function as a spacer. On the other hand, it may bepossible to introduce an aldehyde group into these compounds throughselective oxidation. Sialic acids are found in the human body e.g. asterminal monosaccharides in glycan chains of glycosylated proteins.

In a preferred embodiment, the sialic acid may be selectively oxidizedto an aldehyde group.

Methods to electively oxidize sialic acids or neuramic acids are knownin the art, e.g. from L. W. Jaques, B. F. Riesco, W. Weltner,Carbohydrate Research, 83 (1980), 21-32 and T. Masuda, S. Shibuya, M.Arai, S. Yoshida, T. Tomozawa, A. Ohno, M. Yamashita, T. Honda,Bioorganic & Medicinal Chemistry Letters, 13 (2003), 669-673. Preferablythe oxidation of the sialic acid may be conducted prior to the reactionwith the polymer containing Q, Q being an amino group.

The optionally oxidized sialic acid, may then be reacted via itscarboxylic acid group with the amino group of the polymer.

The resulting compounds contain an aldehyde group which can then furtherbe reacted by reductive amination with an amino group of a protein.

Accordingly, the present invention relates to a method and a conjugateas described above, wherein the polymer derivative comprising Q, Q beingan amino group, is further reacted with an optionally oxidized sialicacid.

As regards pyridoxal phosphate (PyP), this is a highly biocompatiblebifunctional compound and is also called vitamin B6. PyP is a co-enzymewhich participates in transaminations, decarboxylations, racemizations,and numerous modifications of amino acid side chains. All PyP requiringenzymes act via the formation of a Schiff's base between the amino acidand the co-enzyme.

The phosphate group of the PyP may be reacted with the amino group ofthe polymer, preferably hydroxyalkyl starch, in particular hydroxyethylstarch, forming a phosphoramide. The aldehyde group of PyP may then bereacted with the amino group of a protein, forming a Schiff's base,which may then be reduced. In a preferred embodiment, the structure ofthe conjugate is HES-NH—P(O)2-O-(pyridoxal)-CH—NH-protein.

In case of PyP, the functional group Q of the polymer is preferablyintroduced into the polymer by use of a di-amino compound as describedabove.

Accordingly, the present invention relates to a method and a conjugateas described above, wherein the polymer derivative comprising Q, Q beingan amino group, is further reacted with pyridoxal phosphate.

As solvent for the reaction of the polymer derivative comprising anamino group and, e.g., formylbenzoic acid, at least one aprotic solventor at least one polar solvent is preferred. Suitable solvents are, amongothers, water, dimethyl sulfoxide (DMSO), N-methyl pyrrolidone, dimethylacetamide (DMA), dimethyl formamide (DMF) and mixtures of two or morethereof.

As solvent for the reaction of the polymer derivative comprising anamino group and the at least bifunctional compound comprising a carboxygroup, it is also possible to use an aqueous medium. The term “aqueousmedium” as used in this context of the present invention relates to asolvent or a mixture of solvents comprising water in the range of fromat least 10% per weight or at least 20% per weight or at least 30% perweight or at least 40% per weight or at least 50% per weight or at least60% per weight or at least 70% per weight or at least 80% per weight orat least 90% per weight or up to 100% per weight, based on the weight ofthe solvents involved.

The reaction is preferably carried out at a temperature of from 0 to 40°C., more preferably of from 0 to 25° C. and especially preferably offrom 15 to 25° C. for a reaction time preferably of from 0.5 to 24 h andespecially preferably of from 1 to 17 h.

According to a preferred embodiment, the reaction is carried out in thepresence of an activating agent. Suitable activating agents are, amongothers, carbodiimides such as diisopropyl carbodiimde (DIC),dicyclohexyl carbodiimides (DCC),1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), with diisopropylcarbodiimide (DIC) being especially preferred.

The resulting polymer derivative may be purified from the reactionmixture by at least one suitable method. If necessary, the polymerderivative may be precipitated prior to the isolation by at least onesuitable method.

If the polymer derivative is precipitated first, it is possible, e.g.,to contact the reaction mixture with at least one solvent or solventmixture other than the solvent or solvent mixture present in thereaction mixture at suitable temperatures. According to a particularlypreferred embodiment of the present invention where an aqueous medium,preferably water is used as solvent, the reaction mixture is contactedwith 2-propanol or with am mixture of acetone and ethanol, preferably a1:1 mixture (v/v), indicating equal volumes of said compounds, at atemperature, preferably in the range of from −20 to +50° C. andespecially preferably in the range of from −20 to 25° C.

Isolation of the polymer derivative may be carried out by a suitableprocess which may comprise one or more steps. According to a preferredembodiment of the present invention, the polymer derivative is firstseparated off the reaction mixture or the mixture of the reactionmixture with, e.g., aqueous 2-propanol mixture, by a suitable methodsuch as centrifugation or filtration. In a second step, the separatedpolymer derivative may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation. According to an evenmore preferred embodiment, the separated polymer derivative is firstdialysed, preferably against water, and then lyophilized until thesolvent content of the reaction product is sufficiently low according tothe desired specifications of the product. Lyophilisation may be carriedout at temperature of from 20 to 35° C., preferably of from 20 to 30° C.

The resulting polymer derivative with the aldehyde group or keto groupor hemiacetal group is subsequently reacted with an amino group of theprotein via reductive amination. As to the coupling of at least oneamino group of the protein with at least one aldehyde group or ketogroup or hemiacetal group of the polymer by reductive amination,reference is made to the detailed disclosure above concerning thespecific reaction parameters of the reductive amination reaction such aspH or temperature. According to an especially preferred embodiment ofthe present invention, the reductive amination is carried out at atemperature of from 0 to 10° C. such as from 1 to 8° C. or from 2 to 6°C. such as about 4° C. at a pH of about 4.5 to 5.5 such as about 5.0.The reaction time is about 10 to 20 h such as from 12 to 19 h or from 14to 18 h such as about 17 h or about 20 to 30 h such as about 24 h.

Thus, according to the above-mentioned preferred embodiments, thepresent invention also relates, in case the polymer was reacted via itsoxidized reducing end, to a conjugate according to the formula

According to an especially preferred embodiment, the polymer ishydroxyethyl starch, i.e. HAS′ is HES′, and n=2, 3, or 4, mostpreferably 4, as described above. Therefore, in case the polymer wasreacted via its oxidized reducing end, the present invention alsorelates to a conjugate according to the formula

According to another preferred embodiment, the present invention alsorelates, in case the polymer was reacted via its oxidized reducing end,to a conjugate according to the formula

wherein n=2, 3, or 4, R₄ being independently hydrogen or a methoxygroup, and m=0 in case R₄ is hydrogen and m=1 in case R₄ is methoxy, HASpreferably being HES′.

In each of the formulae above, the nitrogen attached to the proteinderives from the amino group of the protein the polymer derivative islinked to via the aldehyde group.

With respect to the above-mentioned embodiments according to which thefunctional groups M and Q comprise an amino group —NH₂, it is alsopossible that M is an amino group —NH₂ and Q comprises a beta hydroxyamino group —CH(OH)—CH₂—NH₂ and preferably is a beta hydroxy aminogroup.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the amino group Q of the compoundcomprising two amino groups M and Q, is a beta hydroxy amino group—CH(OH)—CH₂—NH₂.

In this case, M and Q may be separated by any suitable spacer. Amongothers, the spacer may be an optionally substituted, linear, branchedand/or cyclic hydrocarbon residue. Generally, the hydrocarbon residuehas from 1 to 60, preferably from 1 to 40, more preferably from 1 to 20,more preferably from 2 to 10, more preferably from 1 to 6 and especiallypreferably from 1 to 2 carbon atoms. If heteroatoms are present, theseparating group comprises generally from 1 to 20, preferably from 1 to8 and especially preferably from 1 to 4 heteroatoms. The hydrocarbonresidue may comprise an optionally branched alkyl chain or an aryl groupor a cycloalkyl group having, e.g., from 5 to 7 carbon atoms, or be anaralkyl group, an alkaryl group where the alkyl part may be a linearand/or cyclic alkyl group. According to an even more preferredembodiment, the hydrocarbon residue is an alkyl chain of from 1 to 20,preferably from 1 to 10, more preferably from 1 to 6, more preferablyfrom 1 to 4 carbon atoms and especially preferably from 1 to 2 carbonatoms. Still more preferably, M and Q are separated by a methylenegroup.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is reacted with1,3-diamino-2-hydroxypropane.

In case the polymer is reacted via its oxidized reducing end, a polymerderivative according to the formula results

especially preferably with HAS′=HES′

The reaction of the at least bifunctional compound comprising M and Q,particularly preferably 1,3-diamino-2-hydroxypropane, with the polymeris preferably carried out at a temperature of from 40 to 120° C., morepreferably of from 40 to 90° C. and especially preferably of from 60 to80° C. The reaction time preferably ranges from 17 to 168 h, morepreferably from 17 to 96 h and especially preferably from 48 to 96 h.The molar ratio of at least bifunctional compound:polymer is preferablyin the range of from 200:1 to 10:1, specially from 50:1 to 100:1.

As solvent for the reaction of the at least bifunctional compound withthe polymer, at least one aprotic solvent, preferably an anhydrousaprotic solvent having a water content of not more than 0.5 percent byweight, preferably of not more than 0.1 percent by weight is preferred.Suitable solvents are, among others, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, dimethyl acetamide (DMA), dimethyl formamide (DMF) andmixtures of two or more thereof.

The beta hydroxy amino group Q of the polymer derivative generally maybe reacted with an at least bifunctional compound comprising at leastone functional group capable of being reacted with Q and furthercomprising at least one functional group being an aldehyde group or ketogroup or hemiacetal group or a functional group capable of beingmodified to give an aldehyde group or keto group or hemiacetal group.According to another embodiment of the present invention, the betahydroxy amino group is directly chemically modified to give an aldehydegroup by chemical oxidation.

This oxidation may be carried with all suitable oxidation agents, whichare capable of converting the beta hydroxy amino group to an aldehydegroup. Preferred oxidation reagents are periodates such as alkalinemetal periodates. Especially preferred is sodium periodate which ispreferably employed as aqueous solution. This solution has a preferrediodate concentration of from 1 to 50 mM, more preferably from 1 to 25 mMand especially preferably of from 1 to 10 mM. Oxidation is carried outat a temperature of from 0 to 40° C., preferably from 0 to 25° C. andespecially preferably from 4 to 20° C.

The resulting polymer derivative may be purified from the reactionmixture by at least one suitable method. If necessary, the polymerderivative may be precipitated prior to the isolation by at least onesuitable method.

If the polymer derivative is precipitated first, it is possible, e.g.,to contact the reaction mixture with at least one solvent or solventmixture other than the solvent or solvent mixture present in thereaction mixture at suitable temperatures. According to a particularlypreferred embodiment of the present invention where an aqueous medium,preferably water is used as solvent, the reaction mixture is contactedwith 2-propanol or with am mixture of acetone and ethanol, preferably a1:1 mixture (v/v), indicating equal volumes of said compounds, at atemperature, preferably in the range of from −20 to +50° C. andespecially preferably in the range of from −20 to 25° C.

Isolation of the polymer derivative may be carried out by a suitableprocess which may comprise one or more steps. According to a preferredembodiment of the present invention, the polymer derivative is firstseparated off the reaction mixture or the mixture of the reactionmixture with, e.g., aqueous 2-propanol mixture, by a suitable methodsuch as centrifugation or filtration. In a second step, the separatedpolymer derivative may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation. According to an evenmore preferred embodiment, the separated polymer derivative is firstdialysed, preferably against water, and then lyophilized until thesolvent content of the reaction product is sufficiently low according tothe desired specifications of the product. Lyophilisation may be carriedout at temperature of from 20 to 35° C., preferably of from 20 to 30° C.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the oxidation of the beta hydroxyamino group Q is carried out using a periodate.

Therefore, the present invention also relates to a method of producing aconjugate, wherein, in case the polymer was employed with oxidizedreducing end, a polymer derivative having a beta hydroxy amino group,especially preferably

and particularly with HAS′=HES′, is oxidized, preferably with aperiodate, to a polymer derivative having an aldehyde group, especiallypreferably

and particularly with HAS′=HES′.

According to the present invention, it is also possible to react thecompound comprising an 1-amino 2-hydroxy structure depicted above withan at least bifunctional compound comprising a carboxy group or areactive carboxy group and an aldehyde, keto or acetal group describedhereinabove to obtain a polymer derivative which can be subjected toreductive amination with an amino group of the protein.

The resulting polymer derivative with the aldehyde group A issubsequently reacted with the protein. Therefore, the present inventionalso relates to a method of producing a conjugate, said methodcomprising reacting a polymer derivative having a beta hydroxy aminogroup, in case the polymer was employed with oxidized reducing endespecially preferably according to the formula

and particularly with HAS′=HES′, with an amino group of the protein.

The resulting polymer derivative with the aldehyde group is subsequentlyreacted with an amino group of the protein via reductive amination. Asto the coupling of at least one amino group of the protein with at leastone aldehyde group of the polymer by reductive amination, reference ismade to the detailed disclosure above.

Thus, according to the above-mentioned preferred embodiment, the presentinvention also relates to a conjugate according to the formula

particularly with HAS′=HES′, in case the polymer was employed withoxidized reducing end. In the formula above, the nitrogen attached tothe protein derives from the amino group of the protein the polymerderivative is linked to via the aldehyde group.

According to a further embodiment of the present invention, the polymeris first reacted with a suitable compound to give a first polymerderivative comprising at least one reactive carboxy group. This firstpolymer derivative is then reacted with a further, at least bifunctionalcompound wherein at least one functional group of this further compoundis reacted with at least one reactive carboxy group of the polymerderivative and at least one other functional group of the furthercompound is an aldehyde group or keto group or hemiacetal group or is afunctional group which is chemically modified to give an aldehyde groupor keto group or hemiacetal group, and wherein the resulting polymerderivative comprising said aldehyde group or keto group or hemiacetalgroup is reacted via reductive amination, as described above, with atleast one amino group of the protein. It is also possible to alter thesequence of reacting the respective compounds with each other.

According to a first alternative of said further embodiment, the polymercomprising at least one reactive carboxy group is prepared byselectively oxidizing the polymer at its reducing end and subsequentlyreacting the oxidized polymer being a lactone

and/or a carboxylic acid

or a suitable salt of the carboxylic acid such as alkali metal salt,preferably as sodium and/or potassium salt, and HAS′ preferably beingHES′, with a suitable compound to give the polymer comprising at leastone reactive carboxy group.

Oxidation of the polymer, preferably hydroxyethyl starch, may be carriedout according to each method or combination of methods which result incompounds having the above-mentioned structures (IIa) and/or (IIb).

Although the oxidation may be carried out according to all suitablemethod or methods resulting in the oxidized reducing end of hydroxyalkylstarch, it is preferably carried out using an alkaline iodine solutionas described, e.g., in DE 196 28 705 A1 the respective contents of which(example A, column 9, lines 6 to 24) is incorporated herein byreference.

Introducing the reactive carboxy group into the polymer which isselectively oxidized at its reducing end may be carried out by allconceivable methods and all suitable compounds.

According to a specific method of the present invention, the polymerwhich is selectively oxidized at its reducing end is reacted at theoxidized reducing end with at least one alcohol, preferably with atleast one acidic alcohol such as acidic alcohols having a pK_(A) valuein the range of from 6 to 12 or of from 7 to 11 at 25° C. The molecularweight of the acidic alcohol may be in the range of from 80 to 500g/mole, such as of from 90 to 300 g/mole or of from 100 to 200 g/mole.

Suitable acidic alcohols are all alcohols H—O—R_(A) having an acidicproton and are capable of being with reacted with the oxidized polymerto give the respective reactive polymer ester, preferably according tothe formula

still more preferably according to formula

Preferred alcohols are N-hydroxy succinimides such as N-hydroxysuccinimide or Sulfo-N-hydroxy succinimide, suitably substituted phenolssuch as p-nitrophenol, o,p-dinitrophenol, o,o′-dinitrophenol,trichlorophenol such as 2,4,6-trichlorophenol or 2,4,5-trichlorophenol,trifluorophenol such as 2,4,6-trifluorophenol or 2,4,5-trifluorophenol,pentachlorophenol, pentafluorophenol, or hydroxyazoles such as hydroxybenzotriazole. Especially preferred are N-hydroxy succinimides, withN-hydroxysuccinimide and Sulfo-N-hydroxysuccinimide being especiallypreferred. All alcohols may be employed alone or as suitable combinationof two or more thereof. In the context of the present invention, it isalso possible to employ a compound which releases the respectivealcohol, e.g. by adding diesters of carbonic acid.

Therefore, the present invention also relates to a method as describedabove, wherein the polymer which is selectively oxidised at its reducingend is activated by reacting the oxidised polymer with an acidicalcohol, preferably with N-hydroxy succinimide and/or Sulfo-N-hydroxysuccinimide.

According to a preferred embodiment of the present invention, thepolymer which is selectively oxidized at its reducing end is reacted atthe oxidized reducing end with at least one carbonic diesterR_(B)—O—(C═O)—O—R_(C), wherein R_(B) and R_(C) may be the same ordifferent. Preferably, this method gives reactive polymers according tothe formula

wherein HAS′ is preferably HES′.

As suitable carbonic diester compounds, compounds may be employed whosealcohol components are independently N-hydroxy succinimides such asN-hydroxy succinimide or Sulfo-N-hydroxy succinimide, suitablysubstituted phenols such as p-nitrophenol, o,p-dinitrophenol,o,o′-dinitrophenol, trichlorophenol such as 2,4,6-trichlorophenol or2,4,5-trichlorophenol, trifluorophenol such as 2,4,6-trifluorophenol or2,4,5-trifluorophenol, pentachlorophenol, pentafluorophenol, orhydroxyazoles such as hydroxy benzotriazole. Especially preferred areN,N′-disuccinimidyl carbonate and Sulfo-N,N′-disuccinimidyl carbonate,with N,N′-disuccinimidyl carbonate being especially preferred.

Therefore, the present invention also relates a method as describedabove, wherein the polymer which is selectively oxidised at its reducingend is activated by reacting the oxidised polymer withN,N′-disuccinimidyl carbonate.

The acidic alcohol is reacted with the oxidized polymer or the salt ofthe oxidized polymer at a molar ratio of acidic alcohol:polymerpreferably of from 5:1 to 50:1, more preferably of from 8:1 to 20:1, ata preferred reaction temperature of from 2 to 40° C., more preferably offrom 10 to 30° C. and especially preferably of from 15 to 25° C. Thereaction time is preferably in the range of from 1 to 10 h, morepreferably of from 2 to 5 h, more preferably of from 2 to 4 h andparticularly of from 2 to 3 h.

The carbonic diester compound is reacted with the oxidized polymer orthe salt of the oxidized polymer at a molar ratio of diestercompound:polymer generally of from 1:1 to 3:1, such as of from 1:1 to1.5:1. The reaction time is generally in the range of from 0.1 to 12 h,like of from 0.2 to 6 h, or of from 0.5 to 2 h or of from 0.75 to 1.25h.

According to a preferred embodiment of the present invention, reactingthe oxidized polymer with acidic alcohol and/or carbonic diester iscarried out in at least one aprotic solvent, such as in an anhydrousaprotic solvent having a water content of not more than 0.5 percent byweight, preferably of not more than 0.1 percent by weight. Suitablesolvents are, among others, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, dimethyl acetamide (DMA), dimethyl formamide (DMF) andmixtures of two or more thereof. The reaction temperatures arepreferably in the range of from 2 to 40° C., more preferably of from 10to 30° C.

For reacting the oxidized polymer with the at least one acidic alcohol,at least one additional activating agent is employed.

Suitable activating agents are, among others, carbonyldiimidazole,carbodiimides such as diisopropyl carbodiimide (DIC), dicyclohexylcarbodiimides (DCC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC), with dicyclohexyl carbodiimides (DCC) and1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) being especiallypreferred.

Therefore, the present invention also relates to the method as describedabove, where the polymer which is oxidized at its reducing end and isreacted with an acidic alcohol in the presence of an additionalactivating agent to give the reactive polymer ester.

According to one embodiment of the present invention, the reaction ofthe oxidized polymer with carbonic diester and/or acidic alcohol iscarried out at a low base activity which may be determined by adding thereaction mixture to water with a volume ratio of water to reactionmixture of 10:1. Prior to the addition, the water which comprisesessentially no buffer, has a pH value of 7 at 25° C. After the additionof the reaction mixture and by measuring the pH value, the base activityof the reaction mixture is obtained, having a value of preferably notmore than 9.0, more preferably of nor more than 8.0 and especiallypreferably of not more than 7.5.

According to another embodiment of the present invention, the oxidizedpolymer is reacted with N-hydroxy succinimide in dry DMA in the absenceof water with EDC to selectively give the polymer N-hydroxy succinimideester according to the formula

more preferably with HAS′ being HES′.

Surprisingly, this reaction does not give by-products resulting fromreactions of EDC with OH groups of HES, and the rearrangement reactionof the O-acyl isourea formed by EDC and the oxidized polymer to therespective N-acyl urea is surprisingly suppressed.

According to another preferred embodiment of the present invention, theoxidized polymer is reacted with N,N′-disuccinimidyl carbonate in dryDMF in the absence of water and in the absence of an activating agent toselectively give the polymer N-hydroxy succinimide ester according tothe formula

more preferably with HAS′ being HES′.

According to another embodiment of the present invention, the polymerwhich is selectively oxidized at its reducing end is reacted at theoxidized reducing end with an azolide such as carbonyldiimidazole orcarbonyl dibenzimidazole to give a polymer having a reactive carboxygroup. In the case of carbonyldiimidazole, a reactive imidazolidepolymer derivative according to formula

results, wherein HAS′ is preferably HES′.

According to a second alternative of said further embodiment of thepresent invention regarding the introduction of at least one reactivecarboxy group into the polymer, the reactive carboxy group is introducedinto the polymer whose reducing end is not oxidized, by reacting atleast one hydroxy group of the polymer with a carbonic diester.

Therefore, the present invention also relates to a method and conjugateswherein the reactive carboxy group is introduced in the polymer whosereducing end is not oxidized, by reacting at least one hydroxy group ofthe polymer with at least one carbonic diester carbonic diesterR_(B)—O—(C═O)—O—R_(C), wherein R_(B) and R_(C) may be the same ordifferent.

According to another embodiment of the present invention, the polymerwhose reducing end is not oxidized, is reacted at at least one hydroxygroup with an azolide such as carbonyldiimidazole,carbonyl-di-(1,2,4-triazole) or carbonyl dibenzimidazol to give apolymer having a reactive carboxy group.

As suitable carbonic diester compounds, compounds may be employed whosealcohol components are independently N-hydroxy succinimides such asN-hydroxy succinimide or Sulfo-N-hydroxy succinimide, suitablysubstituted phenols such as p-nitrophenol, o,p-dinitrophenol,o,o′-dinitrophenol, trichlorophenol such as 2,4,6-trichlorophenol or2,4,5-trichlorophenol, trifluorophenol such as 2,4,6-trifluorophenol or2,4,5-trifluorophenol, pentachlorophenol, pentafluorophenol, orhydroxyazoles such as hydroxy benzotriazole.

Especially preferred are symmetrical carbonic diester compounds, R_(B)and R_(C) thus being the same. The alcohol component of the carbonicdiester is preferably selected from the group consisting of N-hydroxysuccinimide, sulfonated N-hydroxy succinimide, N-hydroxy benzotriazole,and nitro- and halogen-substituted phenols. Among others, nitrophenol,dinitrophenol, trichlorophenol, trifluorophenol, pentachlorophenol, andpentafluorophenol are preferred. Especially preferred areN,N′-disuccinimidyl carbonate and Sulfo-N,N′-disuccinimidyl carbonate,with N,N′-disuccinimidyl carbonate being especially preferred.

Therefore, the present invention also relates to a hydroxyalkyl starchderivative, preferably a hydroxyethyl starch derivative, wherein atleast one hydroxy group, preferably at least two hydroxy groups of saidstarch have been reacted with a carbonic diester compound to give therespective reactive ester.

According to one embodiment of the present invention, the reaction ofthe polymer whose reducing end is not oxidized, with the at least onecarbonic diester compound is carried out at a temperature of from 2 to40° C., more preferably of from 10 to 30° C. and especially of from 15to 25° C. A preferred reaction time ranges from 0.5 to 5 h, morepreferably from 1 to 3 h, and especially preferably from 2 to 3 h.

The molar ratio of carbonic diester compound:polymer depends on thedegree of substitution of the polymer regarding the number of hydroxygroups reacted with carbonic diester compound relative to the number ofhydroxy groups present in the non-reacted polymer.

According to one embodiment of the present invention, the molar ratio ofcarbonic diester compound:anhydroglucose units of the polymer is in therange of from 1:2 to 1:1000, more preferably of from 1:3 to 1:100 andespecially preferably of from 1:10 to 1:50, to give a degree ofsubstitution in the range of from 0.5 to 0.001, preferably of from 0.33to 0.01 and especially preferably of from 0.1 to 0.02

According to one embodiment of the present invention, reacting thepolymer whose reducing end is not oxidized, with carbonic diester iscarried out in at least one aprotic solvent, particularly preferably inan anhydrous aprotic solvent having a water content of not more than 0.5percent by weight, preferably of not more than 0.1 percent by weight.Suitable solvents are, among others, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, dimethyl acetamide (DMA), dimethyl formamide (DMF) andmixtures of two or more thereof.

Therefore, the present invention also relates to a method as describedabove wherein the reaction of the at least one hydroxy group of thepolymer whose reducing end is not oxidised, with the carbonic diester togive a reactive carboxy group is carried out in an anhydrous aproticpolar solvent, the solvent preferably being dimethyl acetamide, dimethylformamide or a mixture thereof.

The reactive polymer derivative comprising at least one reactive carboxygroup, preferably resulting from the reaction of the polymer with theacidic alcohol, the carbonate and/or the azolide, as described above, isfurther reacted with a further, at least bifunctional compound whereinat least one functional group F₁ of this further compound is reactedwith at least one reactive carboxy group of the polymer derivative. Asat least one functional group F₁ of the further compound no specificlimitations exist given that a reaction with the at least one reactivecarboxy group of the polymer is possible. Preferred functional groups F₁are, e.g. an amino group or a hydroxy group or a thio group or a carboxygroup.

The further, at least bifunctional compound comprises at least one otherfunctional group F₂ being an aldehyde group or a functional group F₂being capable of being chemically modified to give an aldehyde group.The chemical modification may be, e.g., a reaction of the functionalgroup F₂ with a functional group F₃ a further linker compound or anoxidation or a reduction of a suitable functional group F₂.

In case F₂ is reacted with a functional group F₃ of a further compound,the functional group F₂ may be selected from, among others,

-   -   C—C-double bonds or C—C-triple bonds or aromatic C—C-bonds;    -   the thio group or the hydroxy group;    -   alkyl sulfonic acid hydrazide, aryl sulfonic acid hydrazide;    -   1,2-dioles;    -   1,2-aminoalcohols;        -   1,2 amino-thioalcohols;        -   azides;    -   the amino group —NH₂ or derivatives of the amino groups        comprising the structure unit —NH— such as aminoalkyl groups,        aminoaryl group, aminoaralkyl groups, or alkarlyamino groups;    -   the hydroxylamino group —O—NH₂, or derivatives of the        hydroxylamino group comprising the structure unit —O—NH—, such        as hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxalalkarylamino groups;    -   alkoxyamino groups, aryloxyamino groups, aralkyloxyamino groups,        or alkaryloxyamino groups, each comprising the structure unit        —NH—O—;    -   residues having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,        -   —OH or —SH;        -   an alkoxy group, an aryloxy group, an aralkyloxy group, or            an alkaryloxy group;        -   an alkylthio group, an arylthio group, an aralkylthio group,            or an alkarylthio group;        -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an            aralkylcarbonyloxy group, an alkarylcarbonyloxy group;        -   activated esters such as esters of hydroxylamines having            imid structure such as N-hydroxysuccinimide or having a            structure unit O—N where N is part of a heteroaryl compound            or, with G=O and Q absent, such as aryloxy compounds with a            substituted aryl residue such as pentafluorophenyl,            paranitrophenyl or trichlorophenyl;    -   wherein Q is absent or NH or a heteroatom such as S or O;        -   —NH—NH₂, or —NH—NH—;        -   —NO₂;        -   the nitril group;        -   carbonyl groups such as the aldehyde group or the keto            group;        -   the carboxy group;        -   the —N≡C═O group or the —N═C═S group;    -   vinyl halide groups such as the vinyl iodide or the vinyl        bromide group or triflate;        -   —C≡C—H;        -   —(C═NH₂Cl)—OAlkyl        -   groups —(C═O)—CH₂-Hal wherein Hal is Cl, Br, or I;        -   —CH═CH—SO₂—;        -   a disulfide group comprising the structure —S—S—;    -   the group

-   -   the group

wherein F₃ is a group capable of forming a chemical linkage with one ofthe above-mentioned groups and is preferably selected from theabove-mentioned groups. Moreover, the second linker compound preferablyhas at least one aldehyde group or keto group or hemiacetal group whichis capable of being reacted with an amino group of the protein viareductive amination.

The functional group F₁ and the aldehyde group or keto group orhemiacetal group of the at least bifunctional linking compound which isreacted with the polymer, and/or the functional groups F₁ and F₂ of theat least bifunctional linking compound which is reacted with thepolymer, and/or the functional group F₃ and the aldehyde group or ketogroup or hemiacetal group of the further, at least bifunctional linkingcompound, may be independently separated by any suitable spacer. Amongothers, the spacer may be an optionally substituted, linear, branchedand/or cyclic, aliphatic and/or aromatic hydrocarbon residue. Generally,the hydrocarbon residue has up to 60, preferably up to 40, morepreferably up to 20, more preferably up to 10 carbon atoms. Ifheteroatoms are present, the separating group comprises generally from 1to 20, preferably from 1 to 8, more preferably 1 to 6, more preferably 1to 4 and especially preferably from 1 to 2 heteroatoms. As heteroatom, Ois preferred. The hydrocarbon residue may comprise an optionallybranched alkyl chain or an aryl group or a cycloalkyl group having,e.g., from 5 to 7 carbon atoms, or be an aralkyl group, an alkaryl groupwhere the alkyl part may be a linear and/or cyclic alkyl group.

Examples of a compound with functional groups F₁ and F₂ are, e.g.,optionally substituted diaminoalkane having from 2 to 20 carbon atoms,especially preferably 1,2-diaminoethane, 1,3-diaminopropane, and1,4-diaminobutane. Preferred examples of a compound with functionalgroups F₃ and an aldehyde group or a keto group or a hemiacetal groupare, e.g., formylbenzoic acid, 4-formylbenzoic acid pentafluorophenylester, 4-formylbenzoic acid-N-hydroxysuccinimide ester and4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid.

Therefore, the present invention also relates to a method of producing aconjugate, said method comprising reacting the polymer, preferablyhydroxyethyl starch, at its optionally oxidized reducing end with acompound, selected from the group consisting of acidic alcohols,carbonic diesters and azolides, to give a polymer derivative comprisingat least one reactive carboxy group, reacting said polymer derivativewith at least one at least bifunctional compound to give a polymerderivative comprising an aldehyde group or a keto group or a hemiacetalgroup or a functional group capable of being chemically modified to givean aldehyde group or a keto group or a hemiacetal group, optionallychemically modifying said functional group to give a polymer derivativecomprising an aldehyde group or a keto group or a hemiacetal group, andreacting the polymer derivative comprising an aldehyde group or a ketogroup or a hemiacetal group with an amino group of a protein viareductive amination.

Accordingly, the present invention also relates to a conjugatecomprising a polymer, preferably hydroxyethyl starch, and a proteincovalently linked to each other, obtainable by a method of producing aconjugate, said method comprising reacting the polymer, at itsoptionally oxidized reducing end with a compound, selected from thegroup consisting of acidic alcohols, carbonic diesters and azolides, togive a polymer derivative comprising at least one reactive carboxygroup, reacting said polymer derivative with at least one at leastbifunctional compound to give a polymer derivative comprising analdehyde group or a keto group or a hemiacetal group or a functionalgroup capable of being chemically modified to give an aldehyde group ora keto group or a hemiacetal group, optionally chemically modifying saidfunctional group to give a polymer derivative comprising an aldehydegroup or a keto group or a hemiacetal group, and reacting the polymerderivative comprising an aldehyde group or a keto group or a hemiacetalgroup with an amino group of a protein via reductive amination.

A specific example of a compound having a functional group F₁ and afunctional group F₂ which is oxidized to give an aldehyde group is,e.g., a compound having an amino group as F₁ and a beta hydroxy aminogroup as F₂. An especially preferred example is1,3-diamino-2-hydroxypropane. This oxidation may be carried with allsuitable oxidation agents, which are capable of converting the betahydroxy amino group to an aldehyde group. Preferred oxidation reagentsare periodates such as alkaline metal periodates. Especially preferredis sodium periodate which is preferably employed as aqueous solution.This solution has a preferred iodate concentration of from 1 to 50 mM,more preferably from 1 to 25 mM and especially preferably of from 1 to10 mM. Oxidation is carried out at a temperature of from 0 to 40° C.,preferably from 0 to 25° C. and especially preferably from 4 to 20° C.

The resulting polymer derivative may be purified from the reactionmixture by at least one suitable method. If necessary, the polymerderivative may be precipitated prior to the isolation by at least onesuitable method.

If the polymer derivative is precipitated first, it is possible, e.g. tocontact the reaction mixture with at least one solvent or solventmixture other than the solvent or solvent mixture present in thereaction mixture at suitable temperatures. According to a particularlypreferred embodiment of the present invention where an aqueous medium,preferably water is used as solvent, the reaction mixture is contactedwith 2-propanol or with a mixture of acetone and ethanol, preferably a1:1 mixture (v/v), indicating equal volumes of said compounds, at atemperature, preferably in the range of from −20 to +50° C. andespecially preferably in the range of from −20 to 25° C.

Isolation of the polymer derivative may be carried out by a suitableprocess which may comprise one or more steps. According to a preferredembodiment of the present invention, the polymer derivative is firstseparated off the reaction mixture or the mixture of the reactionmixture with, e.g., aqueous 2-propanol mixture, by a suitable methodsuch as centrifugation or filtration. In a second step, the separatedpolymer derivative may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation. According to an evenmore preferred embodiment, the separated polymer derivative is firstdialysed, preferably against water, and then lyophilized until thesolvent content of the reaction product is sufficiently low according tothe desired specifications of the product. Lyophilisation may be carriedout at temperature of from 20 to 35° C., preferably of from 20 to 30° C.

According to another preferred embodiment of the present invention, thefunctional group Z of the protein to be reacted with functional group Aof the polymer or polymer derivative is a thiol group, wherein theprotein is selected from the group consisting of IFN alpha, IFN beta,tPA, and A1AT. Most preferred are IFN alpha and IFN beta.

The thiol group may be present in the protein as such. Moreover, it ispossible to introduce a thiol group into the protein according to asuitable method. Among others, chemical methods may be mentioned. If adisulfide bridge is present in the protein, it is possible to reduce the—S—S— structure to get a thiol group. It is also possible to transforman amino group present in the polypeptide into a SH group by reactionthe polypeptide via the amino group with a compound which has at leasttwo different functional groups, one of which is capable of beingreacted with the amino group and the other is an SH group or a precursorof an SH group. It is also possible to introduce an SH group by mutationof the protein such as by introducing a cystein or a suitable SHfunctional amino acid into the protein or such as removing a cysteinfrom the protein so as to disable another cystein in the protein to forma disulfide bridge.

Most preferably, the polymer is linked to a free cystein of the protein,especially preferably to the free cystein at position 17 of IFN beta (incase of variants with a cysteine at position 17), to a cystein atposition 1 and/or 98 of IFN alpha.

According to a first embodiment, the functional group Z of the proteinis a thiol group and functional group A of the polymer is ahalogenacetyl group and wherein A is introduced by reacting the polymerat its optionally oxidized reducing end with an at least bifunctionalcompound having at least two functional groups each comprising an aminogroup to give a polymer derivative having at least one functional groupcomprising an amino group and reacting the polymer derivative with amonohalogen-substituted acetic acid and/or a reactivemonohalogen-substituted acetic acid derivative.

As to the at least bifunctional compound having at least two functionalgroups each comprising an amino group, all compounds are conceivablewhich are capable of being reacted with the polymer at its optionallyreducing end to give a polymer derivative comprising an amino groupwhich can be reacted with a monohalogen-substituted acetic acid and/or areactive monohalogen-substituted acetic acid derivative.

According to a preferred embodiment, one functional group of the atleast bifunctional compound, said functional group being reacted withthe optionally oxidized reducing end of the polymer, is selected fromthe group consisting of

wherein G is O or S and, if present twice, independently O or S, and R′is methyl.

According to an especially preferred embodiment of the presentinvention, the functional group of the at least bifunctional compound,said functional group being reacted with the optionally oxidizedreducing end, is the amino group —NH₂. According to a still furtherpreferred embodiment, this functional group, most preferably the aminogroup, is reacted with the oxidized reducing end of the polymer.

According to a preferred embodiment of the present invention, thefunctional group of the at least bifunctional compound, said functionalgroup being reacted with the monohalogen-substituted acetic acid and/ora reactive monohalogen-substituted acetic acid derivative, is an aminogroup —NH₂.

The functional groups, preferably both being an amino group —NH₂, of theat least bifunctional compound, said functional groups being reactedwith the polymer at its optionally oxidized reducing end, preferably theoxidized reducing end, and the monohalogen-substituted acetic acidand/or a reactive monohalogen-substituted acetic acid derivative, may beseparated by any suitable spacer. Among others, the spacer may be anoptionally substituted, linear, branched and/or cyclic hydrocarbonresidue. Suitable substituents are, among others, alkyl, aryl, aralkyl,alkaryl, halogen, carbonyl, acyl, carboxy, carboxyester, hydroxy, thio,alkoxy and/or alkylthio groups. Generally, the hydrocarbon residue hasfrom 1 to 60, preferably from 1 to 40, more preferably from 1 to 20,more preferably from 2 to 10, more preferably from 2 to 6 and especiallypreferably from 2 to 4 carbon atoms. If heteroatoms are present, theseparating group comprises generally from 1 to 20, preferably from 1 to8 and especially preferably from 1 to 4 heteroatoms. The hydrocarbonresidue may comprise an optionally branched alkyl chain or an aryl groupor a cycloalkyl group having, e.g., from 5 to 7 carbon atoms, or be anaralkyl group, an alkaryl group where the alkyl part may be a linearand/or cyclic alkyl group. According to an even more preferredembodiment, the hydrocarbon residue is an alkyl chain of from 1 to 20,preferably from 2 to 10, and especially preferably from 2 to 8 carbonatoms. Thus, preferred at least bifunctional compounds are bifunctionalamino compounds, especially preferably 1,8-diamino octane, 1,7-diaminoheptane, 1,6-diamino hexane, 1,5-diamino pentane, 1,4-diamino butane,1,3-diamino propane, and 1,2-diamino ethane. According to a furtherpreferred embodiment, the at least bifunctional compound is adiaminopolyethylenglycol, preferably a diaminopolyethylenglycolaccording to formulaH₂N—(CH₂—CH₂—O)_(m)—CH₂—CH₂—NH₂

wherein m is an integer, m preferably being 1, 2, 3, or 4.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is reacted with1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane,1,5-diaminopentane, 1,4-diaminobutane, 1,3-diaminopropane, and1,2-diaminoethane at its oxidized reducing end with to give a polymerderivative according to the formula

with n=2, 3, 4, 5, 6, 7, or 8, and the polymer especially preferablybeing HES.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is reacted withH₂N—(CH₂—CH₂—O)_(m)—CH₂—CH₂—NH₂ at its oxidized reducing end, wherein mis 1, 2, 3, or 4, to give a polymer derivative according to the formula

with m=1, 2, 3, or 4, and the polymer especially preferably being HES.

The oxidation of the reducing end of the polymer, preferablyhydroxyethyl starch, may be carried out according to each method orcombination of methods which result in compounds having the structures(IIa) and/or (IIb):

Although the oxidation may be carried out according to all suitablemethod or methods resulting in the oxidized reducing end of hydroxyalkylstarch, it is preferably carried out using an alkaline iodine solutionas described, e.g., in DE 196 28 705 A1 the respective contents of which(example A, column 9, lines 6 to 24) is incorporated herein byreference.

The polymer derivative resulting from the reaction of the polymer withthe at least bifunctional compound is further reacted with themonohalogen-substituted acetic acid and/or a reactivemonohalogen-substituted acetic acid derivative.

As monohalogen-substituted acetic acid or reactive acid, Cl-substituted,Br-substituted and I-substituted acetic acid are preferred.

If the halogen-substituted acid is employed as such, it is preferred toreact the acid with the polymer derivative in the presence of anactivating agent. Suitable activating agents are, among others, Suitableactivating agents are, among others, carbodiimides such as diisopropylcarbodiimide (DIC), dicyclohexyl carbodiimides (DCC),1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), with dicyclohexylcarbodiimides (DCC) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide(EDC) being especially preferred.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer, preferably HES, isreacted with a diamino compound, preferably a diaminoalkane with 2 to 8carbon atoms or H₂N—(CH₂—CH₂—O)_(m)—CH₂—CH₂—NH₂ with m=1, 2, 3, or 4,and reacting the resulting polymer derivative with Br-substituted andI-substituted acetic acid in the presence of an activating agent,preferably EDC.

Therefore, the present invention also relates to a polymer derivativeaccording to the formula

with X═Cl, Br or I, n=2, 3, 4, 5, 6, 7, or 8, and the polymer especiallypreferably being HES, or a polymer derivative according to the formula

with X═Cl, Br or I, m=1, 2, 3, or 4, and the polymer especiallypreferably being HES.

The reaction of the polymer derivative with the halogen-substitutedacetic acid is preferably carried out it in an aqueous system,preferably water, at a preferred pH of from 3.5 to 5.5, more preferablyof 4.0 to 5.0 and especially preferably from 4.5 to 5.0; and a preferredreaction temperature of from 4 to 30° C., more preferably from 15 to 25°C. and especially preferably from 20 to 25° C.; and for a preferredreaction time of from 1 to 8 h, more preferably from 2 to 6 h andespecially preferably from 3 to 5 h.

The reaction mixture comprising the polymer derivative which comprisesthe polymer, the at least bifunctional compound and thehalogen-substituted acetic acid, can be used for the reaction with theprotein as such. According to a preferred embodiment of the presentinvention, the polymer derivative is separated from the reactionmixture, preferably by ultrafiltration, subsequent precipitation,optional washing and drying in vacuo.

The reaction of the polymer derivative with the protein is carried outat a preferred pH of from 6.5 to 8.5, more preferably from 7.0 to 8.5and especially preferably from 7.5 to 8.5; and a preferred reactiontemperature of from 4 to 30° C., more preferably from 15 to 25° C. andespecially preferably from 20 to 25° C.; and for a preferred reactiontime of from 0.5 to 8 h, more preferably from 1 to 6 h and especiallypreferably from 2 to 5 h.

The reaction of the polymer derivative with the thiol group of theprotein results in a thioether linkage between the polymer derivativeand the protein.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer, preferably HES, isreacted with a diamino compound, preferably a diaminoalkane with 2 to 8carbon atoms or H₂N—(CH₂—CH₂—O)_(m)—CH₂—CH₂—NH₂ with m=1, 2, 3, or 4,the resulting polymer derivative is reacted with Br-substituted andI-substituted acetic acid in the presence of an activating agent,preferably EDC, and the resulting polymer derivative is reacted with athiol group of the protein to give a conjugate comprising a thioetherlinkage between the protein and the polymer derivative.

Therefore, the present invention also relates to a conjugate accordingto the formula

with n=2, 3, 4, 5, 6, 7, or 8, and the polymer especially preferablybeing HES and the protein being IFN alpha, IFN beta, tPA, or A1AT,preferably IFN alpha or IFN beta, the S atom being derived from the freecystein at position 17 of IFN beta 1a or a available free cystein, or aconjugate according to the formula

with m=1, 2, 3, or 4, and the polymer especially preferably being HESand the protein being IFN alpha, IFN beta, tPA, or A1AT or APC,preferably IFN alpha or IFN beta, the S atom being derived, e.g., fromthe free cystein at position 17 of IFN beta 1a.

The hydroxyethyl starch is preferably hydroxyethyl starch having a meanmolecular weight of about 10 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 10 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 12 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 12 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 18 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 18 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 30 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 30 kD and a DS of about 0.7, or hydroxyethylstarch having a mean molecular weight of about 50 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 50 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

According to a second embodiment, functional group Z of the protein is athiol group and functional group A of the polymer comprises a maleimidogroup.

According to this embodiment, several possibilities exist to produce theconjugate. In general, the polymer is reacted at its optionally oxidizedreducing end with at least one at least bifunctional compound, whereinthis at least bifunctional compound comprises one functional group whichis capable of being reacted with the optionally oxidized reducing end ofthe polymer, and at least one functional group which either comprisesthe maleimido group or is chemically modified to give a polymerderivative which comprises the maleimido group. According to a preferredembodiment, said functional group is chemically modified to give apolymer derivative which comprises the maleimido group.

Therefore, the present invention relates to a method and a conjugate asdescribed above, by reacting a polymer derivative comprising a maleimidogroup with a thiol group of the protein, said method comprising reactingthe polymer at its optionally oxidized reducing end with an at leastbifunctional compound comprising a functional group U capable ofreacting with the optionally oxidised reducing end, the at leastbifunctional compound further comprising a functional group W capable ofbeing chemically modified to give a maleimido group, the method furthercomprising chemically modifying the functional group W to give amaleimido group.

As to functional group U, each functional group is conceivable which iscapable of being reacted with optionally oxidised reducing end of thepolymer.

According to a preferred embodiment of the present invention, thefunctional group U comprises the chemical structure —NH—.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the functional group U comprisesthe structure —NH—.

According to one preferred embodiment of the present invention, thefunctional group U is a group having the structure R′—NH— where R′ ishydrogen or a alkyl, cycloalkyl, aryl, aralkyl, arylcycloalkyl, alkarylor cycloalkylaryl residue where the cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl or cycloalkylaryl residue may be linked directlyto the NH group or, according to another embodiment, may be linked by anoxygen bridge to the NH group. The alkyl, cycloalkyl, aryl, aralkyl,arylcycloalkyl, alkaryl, or cycloalkylaryl residues may be suitablysubstituted. As preferred substituents, halogenes such as F, Cl or Brmay be mentioned. Especially preferred residues R′ are hydrogen, alkyland alkoxy groups, and even more preferred are hydrogen andunsubstituted alkyl and alkoxy groups.

Among the alkyl and alkoxy groups, groups with 1, 2, 3, 4, 5, or 6 Catoms are preferred. More preferred are methyl, ethyl, propyl,isopropyl, methoxy, ethoxy, propoxy, and isopropoxy groups. Especiallypreferred are methyl, ethyl, methoxy, ethoxy, and particular preferenceis given to methyl or methoxy.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein R′ is hydrogen or a methyl or amethoxy group.

According to another preferred embodiment of the present invention, thefunctional group U has the structure R′—NH—R″— where R″ preferablycomprises the structure unit —NH— and/or the structure unit —(C=G)-where G is O or S, and/or the structure unit —SO₂—. According to morepreferred embodiments, the functional group R″ is selected from thegroup consisting of

where, if G is present twice, it is independently O or S.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the functional group U is selectedfrom the group consisting of

wherein G is O or S and, if present twice, independently O or S, and R′is methyl.

According to a still more preferred embodiment of the present invention,U comprises an amino group —NH₂.

According to an embodiment of the present invention, the functionalgroup W of the at least bifunctional compound is chemically modified byreacting the polymer derivative comprising W with a further at leastbifunctional compound comprising a functional group capable of beingreacted with W and further comprising a maleimido group.

As to functional group W and the functional group of said further atleast bifunctional compound which is capable of being reacted with W,the following functional groups are to be mentioned, among others:

-   -   C—C-double bonds or C—C-triple bonds or aromatic C—C-bonds;    -   the thio group or the hydroxy groups;    -   alkyl sulfonic acid hydrazide, aryl sulfonic acid hydrazide;    -   1,2-dioles;    -   1,2-aminoalcohols;        -   1,2 amino-thioalcohols;        -   azides;    -   the amino group —NH₂ or derivatives of the amino groups        comprising the structure unit —NH— such as aminoalkyl groups,        aminoaryl group, aminoaralkyl groups, or alkarylamino groups;    -   the hydroxylamino group —O—NH₂, or derivatives of the        hydroxylamino group comprising the structure unit —O—NH—, such        as hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxylalkarylamino groups;    -   alkoxyamino groups, aryloxyamino groups, aralkyloxyamino groups,        or alkaryloxyamino groups, each comprising the structure unit        —NH—O—;    -   residues having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,        -   —OH or —SH;        -   an alkoxy group, an aryloxy group, an aralkyloxy group, or            an alkaryloxy group;        -   an alkylthio group, an arylthio group, an aralkylthio group,            or an alkarylthio group;        -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an            aralkylcarbonyloxy group, an alkarylcarbonyloxy group;        -   activated esters such as esters of hydroxylamines having            imid structure such as N-hydroxysuccinimide or having a            structure unit O—N where N is part of a heteroaryl compound            or, with G=O and Q absent, such as aryloxy compounds with a            substituted aryl residue such as pentafluorophenyl,            paranitrophenyl or trichlorophenyl;    -   wherein Q is absent or NH or a heteroatom such as S or O;        -   —NH—NH₂, or —NH—NH—;        -   —NO₂;        -   the nitril group;        -   carbonyl groups such as the aldehyde group or the keto            group;        -   the carboxy group;        -   the —N═C═O group or the —N═C═S group;    -   vinyl halide groups such as the vinyl iodide or the vinyl        bromide group or triflate;        -   —C≡C—H;        -   —(C═NH₂Cl)—OAlkyl        -   groups —(C═O)—CH₂-Hal wherein Hal is Cl, Br, or I;        -   —CH═CH—SO₂—;        -   a disulfide group comprising the structure —S—S—;    -   the group

-   -   the group

where W and the functional group of the further at least bifunctionalcompound, respectively, is a group capable of forming a chemical linkagewith one of the above-mentioned groups.

According to a still more preferred embodiment of the present invention,W comprises an amino group —NH₂.

According to preferred embodiments of the present invention, both W andthe other functional group are groups from the list of groups givenabove.

According to one embodiment of the present invention, one of thesefunctional groups is a thio group. In this particular case, the otherfunctional group is preferably selected from the group consisting of

wherein Hal is Cl, Br, or I, preferably Br or I.

According to an especially preferred embodiment of the presentinvention, one of these functional groups is selected from the groupconsisting of a reactive ester such as an ester of hydroxylamines havingimide structure such as N-hydroxysuccinimide or having a structure unitO—N where N is part of a heteroaryl compound or such as an aryloxycompound with a substituted aryl residue such as pentafluorophenyl,paranitrophenyl or trichlorophenyl, or a carboxy group which isoptionally transformed into a reactive ester. In this particular case,the other functional group comprises the chemical structure —NH—.

According to an especially preferred embodiment of the presentinvention, W comprises the structure —NH— and the further at leastbifunctional compound comprises a reactive ester and the maleimidogroup.

As to the functional group W comprising the structure —NH—, referencecan be made to the functional group as described above, wherein W may bethe same or different from U. According to a preferred embodiment of thepresent invention, U and W are the same. More preferably, both U and Wcomprise an amino group. Particularly preferred, both U and W are anamino group —NH₂.

According to one embodiment of the present invention, the polymer may bereacted with the at least bifunctional compound comprising U and W atits non-oxidized reducing end in an aqueous medium. According to apreferred embodiment where U and W both are an amino group, the reactionis carried out using the polymer with the reducing end in the oxidizedform, in at least one aprotic solvent, particularly preferably in ananhydrous aprotic solvent having a water content of not more than 0.5percent by weight, preferably of not more than 0.1 percent by weight.Suitable solvents are, among others, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, dimethyl acetamide (DMA), dimethyl formamide (DMF) andmixtures of two or more thereof.

Especially in case both U and W are an amino group —NH₂, U and W may beseparated by any suitable spacer. Among others, the spacer may be anoptionally substituted, linear, branched and/or cyclic hydrocarbonresidue. Suitable substituents are, among others, alkyl, aryl, aralkyl,alkaryl, halogen, carbonyl, acyl, carboxy, carboxyester, hydroxy, thio,alkoxy and/or alkylthio groups. Generally, the hydrocarbon residue hasfrom 1 to 60, preferably from 1 to 40, more preferably from 1 to 20,more preferably from 2 to 10, more preferably from 2 to 6 and especiallypreferably from 2 to 4 carbon atoms. If heteroatoms are present, theseparating group comprises generally from 1 to 20, preferably from 1 to8 and especially preferably from 1 to 4 heteroatoms. The hydrocarbonresidue may comprise an optionally branched alkyl chain or an aryl groupor a cycloalkyl group having, e.g., from 5 to 7 carbon atoms, or be anaralkyl group, an alkaryl group where the alkyl part may be a linearand/or cyclic alkyl group. According to an even more preferredembodiment, the hydrocarbon residue is an alkyl chain of from 1 to 20,preferably from 2 to 10, more preferably from 2 to 6, and especiallypreferably from 2 to 4 carbon atoms.

Therefore, the present invention also relates to a method and aconjugate as described above, wherein the polymer is reacted with itsoxidized reducing end with 1,4-diaminobutane, 1,3-diaminopropane or1,2-diaminoethane to give a polymer derivative according to the formula

with n=2, 3, or 4, the polymer preferably being HES.

According to the above-mentioned preferred embodiment, the polymerderivative comprising an amino group is further reacted with an at leastbifunctional compound comprising a reactive ester group and themaleimido group. The reactive ester group and the maleimido group may beseparated by a suitable spacer. As to this spacer, reference can be madeto the spacer between the functional groups U and W. According to apreferred embodiment of the present invention, the reactive ester groupand the maleimido group are separated by a hydrocarbon chain having from1 to 10, preferably from 1 to 8, more preferably from 1 to 6, morepreferably from 1 to 4, more preferably from 1 to 2 and particularlypreferably 1 carbon atom. According to a still further preferredembodiment, the reactive ester is a succinimide ester, and according toa particularly preferred embodiment, the at least bifunctional compoundcomprising the maleimido group and the reactive ester group isN-(alpha-maleimidoacetoxy)succinimide ester.

Therefore, the present invent also relates to a polymer derivativeaccording to the formula

with n=2, 3, or 4, the polymer preferably being HES.

The polymer derivative comprising the maleimido group is further reactedwith the thiol group of the protein to give a conjugate comprising thepolymer derivative linked to the protein via a thioether group.

Therefore, the present invention also relates to a conjugate, comprisingthe protein and the polymer, according to the formula

with n=2, 3, or 4, preferably 4, the polymer preferably being HES, theprotein being IFN alpha, IFN beta, tPA, or A1AT, preferably IFN alpha orIFN beta, and wherein the S atom in the formula above derives, e.g.,from Cys17 of IFN beta 1a.

The hydroxyethyl starch is preferably hydroxyethyl starch having a meanmolecular weight of about 10 kD and a DS of about 0.4 or hydroxyethylstarch having a mean molecular weight of about 10 kD and a DS of about0.7 or hydroxyethyl starch having a mean molecular weight of about 12 kDand a DS of about 0.4 or hydroxyethyl starch having a mean molecularweight of about 12 kD and a DS of about 0.7 or hydroxyethyl starchhaving a mean molecular weight of about 18 kD and a DS of about 0.4 orhydroxyethyl starch having a mean molecular weight of about 18 kD and aDS of about 0.7 or hydroxyethyl starch having a mean molecular weight ofabout 30 kD and a DS of about 0.4 or hydroxyethyl starch having a meanmolecular weight of about 30 kD and a DS of about 0.7 or hydroxyethylstarch having a mean molecular weight of about 50 kD and a DS of about0.4 or hydroxyethyl starch having a mean molecular weight of about 50 kDand a DS of about 0.7 or hydroxyethyl starch having a mean molecularweight of about 100 kD and a DS of about 0.7.

As to each of these combinations of mean molecular weight and DS, also aDS value of about 0.8 is preferred.

The reaction of the polymer derivative comprising the maleimido groupwith the thiol group of the protein is preferably carried in a bufferedaqueous system, at a preferred pH of from 5.5 to 8.5, more preferablyfrom 6 to 8 and especially preferably from 6.5 to 7.5, and a preferredreaction temperature of from 0 to 40° C., more preferably from 0 to 25and especially preferably from 4 to 21° C., and for a preferred reactiontime of from 0.5 to 24 h, more preferably from 1 to 20 h and especiallyfrom 2 to 17 h. The suitable pH value of the reaction mixture may beadjusted by adding at least one suitable buffer. Among the preferredbuffers, sodium acetate buffer, phosphate or borate buffers may bementioned, containing either urea at a preferred concentration of from 0to 8 M, more preferred from 2 to 8 M and especially preferred from 4 to8 M, and/or containing SDS at a preferred concentration of from 0 to 1%(w/v), more preferred from 0.4 to 1% (w/v) and especially prefferd from0.8 to 1% (w/v).

The conjugate may be subjected to a further treatment such as anafter-treatment like dialysis, centrifugal filtration or pressurefiltration, ion exchange chromatography, reversed phase chromatography,HPLC, MPLC, gel filtration and/or lyophilisation.

In the methods for preparing a conjugate of the invention the conversionrate in the above described methods may be at least 50%, more preferredat least 70%, even more preferred at least 80% and in particular 95% oreven more, such as at least 98% or 99%.

The present invention also relates to a conjugate comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII,factor VIII, and factor IX, said conjugate having a structure accordingto the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,wherein G is selected from the group consisting of O and S, preferablyO, and wherein L is an optionally suitably substituted, linear, branchedand/or cyclic hydrocarbon residue, optionally comprising at least oneheteroatom, preferably an alkyl, aryl, aralkyl, heteroaryl,heteroaralkyl residue having from 2 to 60 carbon atoms.

The present invention also relates to a conjugate as described above,wherein -L- is —(CH₂)n- with n=2, 3, 4, 5, 6, 7, 8, 9, 10, preferably 2,3, 4, 5, 6, more preferably 2, 3, 4, and especially preferably 4.

The present invention also relates to a conjugate comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII,factor VIII, and factor IX, said conjugate having a structure accordingto the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein G is selected from the group consisting of O and S,preferably O.

The present invention also relates to a conjugate comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN beta, GM-CSF, APC, tPA, A1AT, AT III, factor VII,factor VIII, and factor IX, said conjugate having a structure accordingto the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally suitably substituted, linear, branchedand/or cyclic hydrocarbon residue, optionally comprising at least oneheteroatom, preferably an alkyl, aryl, aralkyl, heteroaryl,heteroaralkyl residue having from 2 to 60 carbon atoms.

The present invention also relates to a conjugate as described above,wherein -L- is—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)—wherein R_(a); R_(b), R_(c), R_(d) are independently hydrogen, alkyl,aryl, preferably hydrogen,

wherein G is selected from the group consisting of O and S, preferablyO, and wherein

-   -   m 1, 2, 3 or 4, wherein the residues R_(a) and R_(b) may be the        same or different in the m groups C R_(a)R_(b);    -   n 0 to 20, preferably 0 to 10, more preferably 1, 2, 3, 4, 5,        most preferably 1 or 2;        -   o 0 to 20, preferably 0 to 10, more preferably 1, 2, 3, 4,            5, most preferably 1 or 2, wherein the residues R_(C) and            R_(d) may be the same or different in the o groups C            R_(C)R_(d);            wherein the integers for n and o are selected in a way that            in the formula above no peroxy moiety results, e.g. n and o            are not 0 at the same time.

The present invention also relates to a conjugate as described above,wherein R_(a); R_(b), R_(c), R_(d) are hydrogen, m=2, n=1, and o=2.

The present invention also relates to a conjugate comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, said conjugate having astructure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group.

The present invention also relates to a conjugate comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, having a structure according tothe formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein the linkage —O—(C═O)— was formed by a reaction of a carboxygroup or a reactive carboxy group with a hydroxy group of the HASmolecule.

The present invention also relates to a conjugate, comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, said conjugate having astructure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally substituted, linear, branched and/orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom, having from 1 to 60 preferably from 1 to 40, more preferablyfrom 1 to 20, more preferably from 1 to 10, more preferably from 1 to 6more preferably from 1 to 2 carbon atoms and especially preferably 1carbon atom, L being in particular CH₂.

The present invention also relates to a conjugate, comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, said conjugate having astructure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L₁ and L₂ are independently an optionally substituted,linear, branched and/or cyclic hydrocarbon residue, optionallycomprising at least one heteroatom, comprising an alkyl, aryl, aralkylheteroalkyl, and/or heteroaralkyl moiety, said residue having from 1 to60 preferably from 1 to 40, more preferably from 1 to 20, morepreferably from 1 to 10 carbon atoms, and wherein D is a linkage,preferably a covalent linkage which was formed by a suitable functionalgroup F² linked to L₁ and a suitable functional group F₃ linked to L₂.

The present invention also relates to a conjugate as described above,wherein L₁ is —(CH₂)n- with n=2, 3, 4, 5, 6, 7, 8, 9, 10, preferably 2,3, 4, 5, 6, more preferably 2, 3, 4, and especially preferably 4.

The present invention also relates to a conjugate as described above,wherein L₂ comprises an optionally suitably substituted aryl moiety,preferably an aryl moiety containing 6 carbon atoms, L₂ being especiallypreferably C₆H₄.

The present invention also relates to a conjugate as described above,wherein is selected from the group consisting of

-   -   C—C-double bonds or C—C-triple bonds or aromatic C—C-bonds;    -   the thio group or the hydroxy groups;    -   alkyl sulfonic acid hydrazide, aryl sulfonic acid hydrazide;    -   1,2-dioles;    -   1,2 amino-thioalcohols;    -   azides;    -   1,2-aminoalcohols;    -   the amino group —NH₂ or derivatives of the amino groups        comprising the structure unit —NH— such as aminoalkyl groups,        aminoaryl group, aminoaralkyl groups, or alkarlyamino groups;    -   the hydroxylamino group —O—NH₂, or derivatives of the        hydroxylamino group comprising the structure unit —O—NH—, such        as hydroxylalkylamino groups, hydroxylarylamino groups,        hydroxylaralkylamino groups, or hydroxalalkarylamino groups;    -   alkoxyamino groups, aryloxyamino groups, aralkyloxyamino groups,        or alkaryloxyamino groups, each comprising the structure unit        —NH—O—;    -   residues having a carbonyl group, -Q-C(=G)-M, wherein G is O or        S, and M is, for example,        -   —OH or —SH;        -   an alkoxy group, an aryloxy group, an aralkyloxy group, or            an alkaryloxy group;        -   an alkylthio group, an arylthio group, an aralkylthio group,            or an alkarylthio group;        -   an alkylcarbonyloxy group, an arylcarbonyloxy group, an            aralkylcarbonyloxy group, an alkarylcarbonyloxy group;        -   activated esters such as esters of hydroxylamines having            imid structure such as N-hydroxysuccinimide or having a            structure unit O—N where N is part of a heteroaryl compound            or, with G=O and Q absent, such as aryloxy compounds with a            substituted aryl residue such as pentafluorophenyl,            paranitrophenyl or trichlorophenyl;            -   wherein Q is absent or NH or a heteroatom such as S or                O;    -   —NH—NH₂, or —NH—NH—;    -   —NO₂;    -   the nitril group;    -   carbonyl groups such as the aldehyde group or the keto group;    -   the carboxy group;    -   the —N═C═O group or the —N═C═S group;    -   vinyl halide groups such as the vinyl iodide or the vinyl        bromide group or triflate;    -   —C≡C—H;    -   —(C═NH₂Cl)-OAlkyl    -   groups —(C═O)—CH₂-Hal wherein Hal is Cl, Br, or I;    -   —CH═CH—SO₂—;    -   a disulfide group comprising the structure —S—S—;    -   the group

-   -   the group

and wherein F₃ is a functional group capable of forming a chemicallinkage with F₂ and is preferably selected from the above-mentionedgroup, F₂ preferably comprising the moiety —NH—, more preferablycomprising an amino group, F₃ preferably comprising the moiety —(C=G)-,more preferably —(C═O)—, more preferably the moiety —(C=G)-G-, stillmore preferably —(C═O)-G-, and especially preferably —(C═O)—O, D beingparticularly preferably an amide linkage.

The present invention also relates to a conjugate, comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, GM-CSF, APC, tPA, A1AT, AT III,factor VII, factor VIII, and factor IX, said conjugate having astructure according to the formula

wherein the carbon atom of the moiety —CH₂—NH— is derived from analdehyde group which was introduced in the polymer by a ring-openingoxidation reaction, and wherein the nitrogen atom is derived from anamino group of the protein, wherein HAS″ refers to the HAS moleculewithout the carbon atom of said aldehyde involved in the reaction.

The present invention also relates to a conjugate, comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, tPA, A1AT, factor VII and factor IX,said conjugate having a structure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally substituted, linear, branched and/orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom, comprising an alkyl, aryl, aralkyl heteroalkyl, and/orheteroaralkyl moiety, said residue having from 2 to 60 preferably from 2to 40, more preferably from 2 to 20, more preferably from 2 to 10 carbonatoms, and wherein the sulfur atom is derived from a cysteine residue ora disulfide group of the protein.

The present invention also relates to a conjugate as described above,wherein -L- is—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)—wherein R_(a); R_(b), R_(c), R_(d) are independently hydrogen, alkyl,aryl, preferably hydrogen, wherein G is selected from the groupconsisting of O and S, preferably O, and wherein

-   -   m 1, 2, 3 or 4, most preferably 2, wherein the residues R_(a)        and R_(b) may be the same or different in the m groups        (CR_(a)R_(b));    -   n 1 to 20, preferably 1 to 10, most preferably 1, 2, 3, or 4;    -   o 1 to 20, preferably 1 to 10, more preferably 1, 2, 3, 4, 5,        more preferably 1 or 2, most preferably 1, wherein the residues        R_(C) and R_(d) may be the same or different in the o groups        CR_(c)R_(d);        or wherein    -   n 0, and    -   o 2 to 20, preferably 2 to 10, more preferably 2, 3, 4, 5, 6, 7,        or 8, wherein the residues R_(c) and R_(d) may be the same or        different in the o groups CR_(c)R_(d).

The present invention also relates to a conjugate, comprising a proteinand a polymer or a derivative thereof, wherein the polymer is ahydroxyalkyl starch (HAS) and the protein is selected from the groupconsisting of IFN alpha, IFN beta, tPA, A1AT, factor VII and factor IX,said conjugate having a structure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, a hydroxyaryl group, a hydroxyaralkyl group or a hydroxyalkarylgroup having of from 2 to 10 carbon atoms, preferably hydrogen or ahydroxyalkyl group, more preferably hydrogen or a hydroxyethyl group,and wherein L is an optionally substituted, linear, branched and/orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom, comprising an alkyl, aryl, aralkyl heteroalkyl, and/orheteroaralkyl moiety, said residue having from 2 to 60 preferably from 2to 40, more preferably from 2 to 20, more preferably from 2 to 10 carbonatoms, and wherein the sulfur atom is derived from a cysteine residue ora disulfide group of the protein.

The present invention also relates to a conjugate as described above,wherein -L- is—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)—wherein R_(a); R_(b), R_(c), R_(d) are independently hydrogen, alkyl,aryl, preferably hydrogen,

wherein G is selected from the group consisting of O and S, preferablyO, and wherein

-   -   m 1, 2, 3 or 4, most preferably 2, wherein the residues R_(a)        and R_(b) may be the same or different in the m groups        (CR_(a)R_(b));    -   n 1 to 20, preferably 1 to 10, most preferably 1, 2, 3, or 4;    -   o 1 to 20, preferably 1 to 10, more preferably 1, 2, 3, 4, 5,        more preferably 1 or 2, most preferably 1, wherein the residues        R_(C) and R_(d) may be the same or different in the o groups        CR_(c)R_(d);        or wherein    -   n 0, and    -   o 2 to 20, preferably 2 to 10, more preferably 2, 3, 4, 5, 6, 7,        or 8, wherein the residues R_(C) and R_(d) may be the same or        different in the o groups CR_(c)R_(d).

The present invention also relates to a conjugate as described above,wherein the hydroxyalkyl starch is hydroxyethyl starch.

The present invention also relates to a conjugate as described above,wherein the hydroxyethyl starch has a molecular weight of from 2 to 200kD, preferably of from 4 to 130 kD, more preferably of from 4 to 70 kD.

According to a further aspect, the present invention relates to aconjugate as described above, or a conjugate, obtainable by a method asdescribed above, for use in a method for the treatment of the human oranimal body.

The conjugates according to the invention may be at least 50% pure, evenmore preferred at least 70% pure, even more preferred at least 90%, inparticular at least 95% or at least 99% pure. In a most preferredembodiment, the conjugates may be 100% pure, i.e. there are no otherby-products present.

Therefore, according to another aspect, the present invention alsorelates to a composition which may comprise the conjugate(s) of theinvention, wherein the amount of the conjugate(s) may be at least 50wt-%, even more preferred at least 70 wt-%, even more preferred at least90 wt-%, in particular at least 95 wt.-% or at least 99 wt.-%. In a mostpreferred embodiment, the composition may consist of the conjugate(s),i.e. the amount of the conjugate(s) is 100 wt.-%.

Furthermore, the present invention relates to a pharmaceuticalcomposition comprising in a therapeutically effective amount a conjugateas described above or a conjugate, obtainable by a method as describedabove.

All protein-HAS conjugates of the present invention are administered bysuitable methods such as e.g. entheral, parentheral or pulmonary methodspreferably administered by i.v., s.c. or i.m. routes. The specific routechosen will depend upon the condition being treated. Preferably, theconjugates are administered together with a suitable carrier, such asknown in the art (e.g. as used in the first generation/unmodifiedbiopharmaceutical, albumin-free or with albumin as an excipient), asuitable diluent, such as sterile solutions for i.v., i.m., or s.c.application. The required dosage will depend on the severity of thecondition being treated, the patients individual response, the method ofadministration used, and the like. The skilled person is able toestablish a correct dosage based on his general knowledge.

According to another aspect, the present invention also relates to theuse a HAS-, preferably a HES-protein conjugate as described above or aHAS-, preferably a HES-protein conjugate, obtainable by a method asdescribed above, wherein the protein is Factor VIII, for the preparationof a medicament for the treatment of haemophilia A.

According to another aspect, the present invention also relates to theuse of a HAS-AT III conjugate as described above or a HAS-proteinconjugate, obtainable by a method as described, for the preparation of amedicament for the treatment of AT III hereditary deficiency,veno-Occlusive disease, burns and heparin resistance in coronaryarterial bypass Graft (CABG) surgery, bowel perforation resulting fromtrauma or gastrointestinal surgery; disseminated intravascularcoagulation (DIC) and/or sepsis as well as for the prevention ofmicro-clot formation associated with ventilation therapy. Thepharmaceutical composition comprising the HAS-AT III conjugate of theinvention may therefore be used for these purposes.

According to another aspect, the present invention also relates to theuse a HAS-, preferably a HES-protein conjugate as described above or aHAS-, preferably a HES-protein conjugate, obtainable by a method asdescribed above, wherein the protein is A1AT, for the preparation of amedicament for the treatment of emphysema, cystic fibrosis, atopicdermatitis, and/or bronchitis. The pharmaceutical composition of theinvention comprising the HAS-A1AT-conjugate of the invention may also beused for these purposes.

According to another aspect, the present invention also relates to theuse a HAS-, preferably a HES-protein conjugate as described above or aHAS-, preferably a HES-protein conjugate, obtainable by a method asdescribed above, wherein the protein is tPA, for the preparation of amedicament for the treatment of myocardial infarctions (heart attacks),thrombosis, thromboembolim or occlusive diseases, especially occlusivearterial diseases.

According to another aspect, the present invention also relates to theuse a HAS-, preferably a HES-protein conjugate as described above or aHAS-, preferably a HES-protein conjugate, obtainable by a method asdescribed above, wherein the protein is APC, for the preparation of amedicament for the treatment of severe sepsis, thrombosis,thromboembolim or occlusive diseases, especially occlusive arterialdiseases.

According to another aspect, the present invention also relates to theuse a HAS-, preferably a HES-protein conjugate as described above or aHAS-, preferably a HES-protein conjugate, obtainable by a method asdescribed above, wherein the protein is IFN alpha, for the preparationof a medicament for the treatment of leukemia e.g. hairy cell leukemia,chronic myelogeneous leukemia, multiple myeloma, follicular lymphoma,cancer, e.g. carcinoid tumour, malignant melanoma and hepatitis, eg.chronic hepatitis B and chronic hepatitis C.

According to another aspect, the present invention also relates to theuse a HAS-, preferably a HES-protein conjugate as described above or aHAS-, preferably a HES-protein conjugate, obtainable by a method asdescribed above, wherein the protein is IFN beta, for the preparation ofa medicament for the treatment of multiple sclerosis, preferablyrelapsing forms of multiple sclerosis.

The invention further relates to the use of a GM-CSF-HAS conjugate asdescribed above, for the preparation of a medicament for myeloidreconstitution following bone marrow transplant or inductionchemotherapy in older adults with acute myelogenous leukemia, bonemarrow transplant engraftment failure or delay, mobilization andfollowing transplantation of autologous peripheral blood progenitorcells.

The present invention also relates to the use of a HAS-Factor VIIconjugate for the preparation of a medicament for the treatment ofepisodes in hemophilia A or B patients with inhibitors to Factor VIII orFactor IX.

The present invention also relates to the use of a HAS-Factor IXconjugate for the preparation of a medicament for the control andprevention of hemorrhagic episodes in patients with hemophillia B (e.g.congenital factor IX deficiency or Christmas disease), including controland prevention of bleeding in surgical settings.

The invention will be further described in the following examples, whichdo not limit the scope of the invention described in the claims.

EXAMPLES Example 1 Synthesis of IFN Beta Conjugates Example 1.1Synthesis of Hydroxyamino Functionalized Hydroxyethyl Starch DerivativesExample 1.1(a) Synthesis of HydroxylaminoHES10/0.4

2 g of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 17 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 1.1(b) Synthesis of HydroxylaminoHES10/0.7

2 g of HES10/0.7 (MW=10000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 18 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES10/0.7 when measured with LALLS-GPC was10500 D and the DS was 0.76.

Example 1.1(c) Synthesis of HydroxylaminoHES50/0.7

2 g of HES50/0.7 (MW=50000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 20 mL 0.1M sodium acetate buffer,pH 5.2 and 4 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES50/0.7 when measured with LALLS-GPC was47000 D and the DS was 0.76.

Example 1.1(d) Synthesis of HydroxylaminoHES50/0.4

2 g of HES50/0.4 (MW=50000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 20 mL 0.1M sodium acetate buffer,pH 5.2 and 4 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 17.5 h at 22° C., the reaction mixture wasadded to 70 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v).The precipitated product was collected by centrifugation at 0° C.,washed with 30 mL of an ice-cold 1:1 mixture of acetone and ethanol(v/v), re-dissolved in 50 mL water, dialysed for 19.5 h against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized.

The molecular weight of the HES50/0.4 when measured with LALLS-GPC was56000 D and the DS was 0.41.

Example 1.1(e) Synthesis of HydroxylaminoHES18/0.4

Oxidized HES was prepared as described in DE 196 28 705 A1. 200 mg ofoxidized HES18/0.4 (MW=18000 D, DS=0.4) were heated at 80° C. in vacuofor 17 h and dissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich ChemieGmbH, Taufkirchen, D). To the solution 2 mmolO-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine were added. Afterincubation for 5 d at 65° C., the reaction mixture was added to 20 mL ofice-cold 2-propanol and was incubated at −20° C. for 1 h. Theprecipitated product was collected by centrifugation at 4° C., washedwith 42 ml ice-cold 2-propanol, re-dissolved in 10 mL water, dialysedfor 27 h against water (SnakeSkin dialysis tubing, 3.5 kD cut off,Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES18/0.4 when measured with LALLS-GPC was18000 D and the DS was 0.41.

Example 1.1(f) Synthesis of HydrazidoHES10/0.4

Oxidized HES was prepared as described in DE 196 28 705 A1. 200 mg ofoxidized HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were heated at 80° C. in vacuo for 17 h anddissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmol adipic dihydrazide (LancasterSynthesis GmbH, Frankfurt/Main D) were added. After incubation for 5 dat 65° C., the reaction mixture was added to 20 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was11000 D and the DS was 0.41.

Example 1.1(g) Synthesis of CarbohydrazidoHES10/0.4

Oxidized HES was prepared as described in DE 196 28 705 A1. 200 mg ofoxidized HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were heated at 80° C. in vacuo for 17 h anddissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmol carbohydrazide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationfor 5 d at 65° C., the reaction mixture was added to 20 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was11000 D and the DS was 0.41.

Example 1.1(h) Synthesis of HydrazidoHES10/0.4

200 mg of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 2 mL 0.1M sodium acetatebuffer, pH 5.2. To the solution 2 mmol adipic dihydrazide (LancasterSynthesis GmbH, Frankfurt/Main D) were added. After stirring for 19 h at22° C., the reaction mixture was added to 21 mL of ice-cold 2-propanoland was incubated at −20° C. for 1 h. The precipitated product wascollected by centrifugation at 4° C., washed with 42 ml ice-cold2-propanol, re-dissolved in 10 mL water, dialysed for 27 h against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 1.1(i) Synthesis of CarboydrazidoHES10/0.4

200 mg of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 2 mL 0.1M sodium acetatebuffer, pH 5.2. To the solution 2 mmol carbohydrazide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After stirringfor 19 h at 22° C., the reaction mixture was added to 21 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 1.2 Synthesis of the IFN Beta Conjugates Example 1.2(a)Oxidation of IFN Beta

Recombinant human interferon beta-1a comprising identical amino acidsequence as the market products AVONEX™ (BIOGEN) and Rebif (Serono) andwas expressed from a CHO cell line transfected as described (Dittmar etal., 1989) and purified as described in Example 6.1. Oxidation wasessentially as described in Example 6.2, followed by buffer exchange asdescribed in Example 6.3.

Example 1.2(b) Reaction of Oxidized IFN-Beta of Example 1.2(a) with HESDerivatives of Examples 1.1(a)-1.1(i)

To 25.9 μL of a solution of oxidized IFN-beta in 0.1 M sodium acetatebuffer, pH 5.5, 5.27 μL of a solution of the HES-derivative in 0.1 Msodium acetate buffer, pH 5.5 were added and the solution was incubatedfor 16.5 h at 22° C. The following concentrations were employed:

-   (i) 78.9 mg/mL for HES derivatives prepared according to example    1.1(a), 1.1(b), 1.1(f), 1.1(g), 1.1(h) and 1.1(j)-   (ii) 395 mg/mL for HES derivatives prepared according to example    1.1(c) and 1.1(d)-   (iii) 142 mg/mL for HES derivative prepared according to example    1.1(e)

The respective reaction mixture was analysed by gel electrophoresis (seeFIG. 1).

Example 1.3 Synthesis of Aldehyde Functionalized Hydroxyethyl StarchDerivatives Example 1.3(a) Synthesis of Aldehydo-HES10/0.4 fromAmino-HES10/0.4 and 4-formylbenzoic Acid

Oxo-HES10/0.4 (MW=10 kD, DS=0.4) was prepared by Supramol Parenteral

Colloids GmbH, Rosbach-Rodheim, D; according to DE 196 28 705 A1. Themolecular weight of the HES10/0.4 when measured with LALLS-GPC was 14500D and the DS was 0.41.

5.1 g (0.51 mmol) of oxo-HES10/0.4 were dissolved in 15 ml anhydrousdimethyl sulfoxide (DMSO, Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen,D)) and added dropwise under nitrogen to a solution of 5.1 ml (51 mmol)1,4-diaminobutane in 10 ml anhydrous dimethyl sulfoxide and stirred at40° C. for 19 h. The reaction mixture was added to a mixture of 80 mlethanol and 80 ml acetone. The resulting precipitate was separated bycentrifugation, washed with a mixture of 20 ml ethanol and 20 ml acetoneand re-dissolved in 80 ml water. The solution was dialyzed for 4 daysagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio ScienceDeutschland GmbH, Bonn, D) and subsequently lyophilized. The yield was67% (3.4 g) amino-HES10/0.4.

150 mg 4-formylbenzoic acid and 230 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 10ml N,N-dimethylformamide (peptide synthesis grade, Biosolve,Valkenswaard, NL) and 204 μl N,N′-diisopropylcarbodiimide were added.After incubation at 21° C. for 30 min, 1 g of the amino-HES10/0.4 wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 84 ml of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 ml water, dialysed for 2 d against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

Example 1.3(b) Synthesis of Aldehydo-HES10/0.4 by Periodate Oxidation ofHES10/0.4 Oxidized at its Reducing End

Oxo-HES10/0.4 (MW=10 kD, DS=0.4) was prepared by Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D; according to DE 196 28 705 A1. Themolecular weight of the HES10/0.4 when measured with LALLS-GPC was 8500D and the DS was 0.41.

300 mg of oxo-HES10/0.4 were dissolved in 15 ml 20 mM sodium phosphatebuffer, pH 7.2. 64.2 mg sodium periodate (Fluka, Sigma-Aldrich ChemieGmbH, Taufkirchen, D) were dissolved in 15 ml of the same buffer. Bothsolutions were mixed and after incubation for 30 min at 21° C., 2 mlglycerol were added and the reaction mixture was incubated at 21° C. for10 min. The reaction mixture was dialysed for 24 h against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized.

Example 1.4 Synthesis of IFN Beta Conjugates by Reductive Amination withAldehyde Functionalized Hydroxyethyl Starch Synthesized According toExamples 1.3(a) and 1.3(b)

Recombinant human interferon beta-1a comprising identical amino acidsequence as the market products AVONEX™ (BIOGEN) and Rebif (Serono) andwas expressed from a CHO cell line transfected as described (Dittmar etal., 1989) and purified as described in Example 6.1.

To 40 μl of a solution of IFN beta in 0.1 M sodium acetate buffer pH 5.0(0.5 mg/ml 5 μl of a solution of the HES-derivative (synthesized asdescribed in Examples 1.3(a) or 1.3(b)) in the same buffer (200 mg/mL)were added. The mixture was cooled to 4° C. and 9 μl of a 120 mMsolution of sodium cyanoborohydride in the same buffer at 4° C. wereadded and the mixture was incubated for 24 h at 4° C. The crude reactionmixture was analysed by gel electrophoresis. A successful conjugationwas observed, as indicated by the migration of the protein band tohigher molecular weight (see FIG. 2). The increased band-width is due tothe molecular weight distribution of the HES derivative used and thenumber of HES derivatives linked to the protein.

Example 1.5 Description of IFN Beta Antiviral Activity Bioassay

General Remarks

In the European Pharmacopeia, currently only assays are given for thedetermination of the activity of Interferon-α and Interferon-γ. However,because the antiviral potency of Interferon-α is measured in these testsusing an in vitro cytopathic effect (CPE) bioassay as described inSupplement 2001 (chapter 5.6) and as it is applied for the IFN-β drugproducts approved to date, antiviral activity can be tested in analogyto Interferon-α.

The antiviral activity of IFN-β can be tested utilizing a specific invitro cytopathic effect bioassay e.g. with lung carcinoma cells (A549)and encephalomyo-carditis virus (EMCV). Other possible combinations,which can be used for the determination of the antiviral activity ofinterferons are WISH cell lines or Madin-Darby bovine kidney (MDBK) celllines and VSV (vesicular stomatis virus).

Interferon Antiviral Assay—Outline

In a first step the in vitro antiviral activity ofHES-IFN-beta-conjugates was compared to unmodified IFN-beta.

In the CPE assay (MDBK/VSV), dilutions of standard interferon andHES-IFN-beta-conjugate were compared. The cells were pretreated with thetest samples for about 48 h before they were brought into contact withthe virus.

After an incubation period (ca. 22 h), the protective effect of theinterferon against the viral cytopathic effect was estimated.

Interferon Antiviral Assay—Experimental Details

The following steps were performed:

-   -   Interferon solutions were pre-diluted in cell culture medium for        MDBK cells (1:10)

These solutions were sequentially diluted to 1:2-1:2,097,152 (=1:2²¹)

-   -   4 replicates (100 μl each well)    -   fresh trypsinated MDBK cells were added (5,000 cells/well in 50        μl)    -   Incubation: 48 hours at 37° C.    -   50 μl prediluted VSV solution was added (250 viruses/well)    -   Incubation: 22 hours at 37° C.    -   Determination of the protective effect of the Interferon against        viral cytopathic effect    -   Calculation of Interferon titer using the Spearman-Kärber's        method

Controls:

MDBK-cells with Interferon-solutions, no virus (negative control)

MDBK-cells without Interferon with virus (positive control)

Results:

Two Interferon beta samples and the respective HES-conjugates weretested in the CPE assay using two different dilutions (estimated1,000,000 IU/ml and 200,000 IU/ml).

The interferon titer was calculated according to the formula of Spearmanand Kärber. The ratio of the activities of the different samples wascalculated. Taking into account the estimated specific activity of thesamples, the EC50 concentrations, at which 50% of the cells areprotected against the virus incubation, were calculated and compared(data not shown).

The modified IFN-beta retained bioactivity.

Example 2 Synthesis of IFN Alpha Conjugates Example 2.1(a) Synthesis ofAldehydo-HES10/0.4 from Amino-HES10/0.4 and 4-formylbenzoic Acid

Aldehydo-HES10/0.4 was prepared according to Example 1.3(a).

Example 2.1(b) Synthesis of Aldehydo-HES10/0.4 from Amino-HES10/0.4 and4-formylbenzoic Acid

Aldehydo-HES10/0.4 was prepared according to Example 1.3(b).

Example 2.2 Synthesis of IFN Alpha Conjugates by Reductive Aminationwith Aldehyde Functionalized Hydroxyethyl Starch Synthesized Accordingto Examples 2.1(a) and 2.1(b)

Commercially available rhIFN alpha was used (Strathmann Biotec, Hamburg,D, product code hIFNa) was used.

To 15 μl of a solution of IFN beta in 0.1 M sodium acetate buffer pH 5.0(1 mg/ml) 3.91 μl of a solution of the HES-derivative (synthesized asdescribed in Examples 2.1(a) or 0.21(b)) in the same buffer (200 mg/mL)were added. The mixture was cooled to 4° C. and 3.78 μl of a 120 mMsolution of sodium cyanoborohydride in the same buffer at 4° C. wereadded and the mixture was incubated for 24 h at 4° C. The crude reactionmixture was analysed by gel electrophoresis. A successful conjugationwas observed, as indicated by the migration of the protein band tohigher molecular weight (see FIG. 3). The increased band-width is due tothe molecular weight distribution of the HES derivatives used and thenumber of HES derivatives linked to the protein.

Example 3 Synthesis of AT III conjugates Example 3.1 Synthesis ofHydroxyamino Functionalized Hydroxyethyl Starch Derivatives Example3.1(a) Synthesis of HydroxylaminoHES10/0.4

2 g of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 17 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 3.1(b) Synthesis of HydroxylaminoHES10/0.7

2 g of HES10/0.7 (MW=10000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 18 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES10/0.7 when measured with LALLS-GPC was10500 D and the DS was 0.76.

Example 3.1(c) Synthesis of HydroxylaminoHES50/0.7

2 g of HES50/0.7 (MW=50000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 20 mL 0.1M sodium acetate buffer,pH 5.2 and 4 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES50/0.7 when measured with LALLS-GPC was47000 D and the DS was 0.76.

Example 3.1(d) Synthesis of HydroxylaminoHES18/0.4

Oxidized HES was prepared essentially as described in DE 19628705A1. 200mg of oxidized HES18/0.4 (MW=18000 D, DS=0.4) were heated at 80° C. invaccuo for 17 h and dissolved in 2 mL dry DMSO (Fluka, Sigma-AldrichChemie GmbH, Taufkirchen, D). To the solution 2 mmolO-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine were added. Afterincubation for 5 d at 65° C., the reaction mixture was added to 20 mL ofice-cold 2-propanol and was incubated at −20° C. for 1 h. Theprecipitated product was collected by centrifugation at 4° C., washedwith 42 ml ice-cold 2-propanol, re-dissolved in 10 mL water, dialysedfor 27 h against water (SnakeSkin dialysis tubing, 3.5 kD cut off,Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES18/0.4 when measured with LALLS-GPC was18000 D and the DS was 0.41.

Example 3.1(e) Synthesis of HydrazidoHES10/0.4

Oxidized HES was prepared essentially as described in DE 19628705A1. 200mg of oxidized HES10/0.4 (MW=10000 D, DS=0.4, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D) were heated at 80° C. in vaccuo for17 h and dissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmol adipic dihydrazide (LancasterSynthesis GmbH, Frankfurt/Main D) were added. After incubation for 5 dat 65° C., the reaction mixture was added to 20 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was11000 D and the DS was 0.41.

Example 3.1(f) Synthesis of CarbohydrazidoHES10/0.4

Oxidized HES was prepared essentially as described in DE 19628705A1. 200mg of oxidized HES10/0.4 (MW=10000 D, DS=0.4, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D) were heated at 80° C. in vaccuo for17 h and dissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmol carbohydrazide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationfor 5 d at 65° C., the reaction mixture was added to 20 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was11000 D and the DS was 0.41.

Example 3.1(g) Synthesis of HydrazidoHES10/0.4

200 mg of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 2 mL 0.1M sodium acetatebuffer, pH 5.2. To the solution 2 mmol adipic dihydrazide (LancasterSynthesis GmbH, Frankfurt/Main D) were added. After stirring for 19 h at22° C., the reaction mixture was added to 21 mL of ice-cold 2-propanoland was incubated at −20° C. for 1 h. The precipitated product wascollected by centrifugation at 4° C., washed with 42 ml ice-cold2-propanol, re-dissolved in 10 mL water, dialysed for 27 h against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 3.1(h) Synthesis of CarboydrazidoHES10/0.4

200 mg of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 2 mL 0.1M sodium acetatebuffer, pH 5.2. To the solution 2 mmol carbohydrazide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After stirringfor 19 h at 22° C., the reaction mixture was added to 21 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 3.2 Synthesis of AT III Conjugates Example 3.2(a) Oxidation ofAT III

AT III used was recombinant human AT III (ATryn® from GTCBiotherapeutics).

Oxidation was essentially as described in Example 7.2, followed bybuffer exchange as described in Example 7.3.

Example 3.2(b) Reaction of Oxidized AT III of Example 3.2(a) with HESDerivatives of Examples 3.1(a)-3.1(h)

To 4 μL of a solution of oxidized ATIII in 0.1 M sodium acetate buffer,pH 5.5, 3 μL of a solution of the HES-derivative in 0.1 M sodium acetatebuffer, pH 5.5 were added and the solution was incubated for 16.5 h at22° C. The following concentrations were employed:

-   (i) 57 mg/mL for HES derivatives prepared according to example    3.1(a), 3.1(b), 3.1(e), 3.1(f), 3.1(g) and 3.1(h)-   (ii) 287 mg/mL for HES derivatives prepared according to example    3.1(c)-   (iii) 103 mg/mL for HES derivative prepared according to example    3.1(d)

The reaction mixture was analysed by gel electrophoresis (see FIG. 4).

Example 3.3 Synthesis of AT III Conjugates Example 3.3(a) Synthesis ofAldehydo-HES10/0.4 from Amino-HES10/0.4 and 4-formylbenzoic Acid

Aldehydo-HES10/0.4 was prepared according to Example 1.3(a).

Example 3.3(b) Synthesis of aldehydo-HES10/0.4 from Amino-HES10/0.4 and4-formylbenzoic Acid

Aldehydo-HES10/0.4 was prepared according to Example 1.3(b).

Example 3.4 Synthesis of AT III Conjugates by Reductive Amination withAldehyde Functionalized Hydroxyethyl Starch Synthesized According toExamples 3.3(a) and 3.3(b)

AT III used was recombinant human AT III (ATryn® from GTCBiotherapeutics).

To 6.67 μl of a solution of AT III in 0.1 M sodium acetate buffer pH 5.0(3 mg/ml) 1.73 μl of a solution of the HES-derivative (synthesized asdescribed in Examples 3.3(a) or 3.3(b)) in the same buffer (200 mg/mL)were added. The mixture was cooled to 4° C. and 1.68 μl of a 120 mMsolution of sodium cyanoborohydride in the same buffer at 4° C. wereadded and the mixture was incubated for 24 h at 4° C. The crude reactionmixture was analysed by gel electrophoresis. A successful conjugationwas observed, as indicated by the migration of the protein band tohigher molecular weight (see FIG. 5). The increased band-width is due tothe molecular weight distribution of the HES derivative used and thenumber of HES derivatives linked to the protein.

Example 3.5 Synthesis of AT III Conjugates by Reaction of HydroxyethylStarch Having a Reactive Ester Group with AT III

An AT III solution with a concentration of about 25 mg/ml in a 5 mMsodium citrate buffer, 66 mM glycerol, 67 mM NaCl, pH about 7 was usedfor this Example.

AT III used was recombinant human AT III (ATryn® from GTCBiotherapeutics).

AT III was liberated from unwanted glycerol by ultrafiltration with aphosphate buffer, pH 7.2, and a membrane with a cut-off of 10 kD. Thefinal concentration of the resulting purified solution was about 25mg/1.25 ml. The quality of the protein was controlled by HPGPC analysis(see FIG. 6).

The following parameters were used in the HPGPC analysis:

Column: Superose 12 HR 10/30 300 × 10 mm I.D. (Pharmacia) Eluent: 27.38mM Na₂HPO₄; 12.62 mM NaH₂PO₄; 0.2M NaCl; 0.005% NaN₃ in 1 l ofdemineralized water Flux: 0.24 ml/h Detector 1: MALLS detector Detector2: UV (280 nm) Detector 3: RI

Oxo-HES10/0.4 (MW=10,559 D, DS=0.4) was prepared by Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D; according to DE 196 28 705 A1. Thedegree of oxidation of oxo-HES was 95%

52 mg of oxo-HES10/0.4 were dissolved in 0.2 ml anhydrous DMF. To thissolution, 2.6 mg of N,N′-disuccinimidyl carbonate were added, and themixture was stirred for 2 h at room temperature.

0.5 ml of 1 M sodium bicarbonate solution were added to 0.5 ml of the ATIII solution resulting in a solution having a concentration of about 10mg/ml AT III, pH 8.2. To this solution, the solution containing thereactive oxo-HES, as prepared above, was added in portions of 50 μluntil, after about 30 min., the reaction had come to an end. Then, thepH of the mixture was adjusted to 7 using 0.1 N HCl and freezed at −18°C. until A HPGPC analysis (High-Performance Gel PermeationChromatography) gave a yield of about 60% conjugate. This result isshown in FIG. 7.

The following parameters were used in the HPGPC analysis:

Column: Superose 12 HR 10/30 300 × 10 mm I.D. (Pharmacia) Eluent: 27.38mM Na₂HPO₄; 12.62 mM NaH₂PO₄; 0.2M NaCl; 0.005% NaN₃in 1 l ofdemineralized water Flux: 0.24 ml/h Detector 1: MALLS detector Detector2: UV (280 nm) Detector 3: RI

Example 4 Synthesis of GM-CSF Conjugates Example 4.1 Synthesis ofHydroxyamino Functionalized Hydroxyethyl Starch Derivatives Example4.1(a) Synthesis of HydroxylaminoHES10/0.4

2 g of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 17 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 4.1(b) Synthesis of HydroxylaminoHES10/0.7

2 g of HES10/0.7 (MW=10000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 18 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES10/0.7 when measured with LALLS-GPC was10500 D and the DS was 0.76.

Example 4.1(c) Synthesis of HydroxylaminoHES50/0.7

2 g of HES50/0.7 (MW=50000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 20 mL 0.1M sodium acetate buffer,pH 5.2 and 4 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized.

The molecular weight of the HES50/0.7 when measured with LALLS-GPC was47000 D and the DS was 0.76.

Example 4.1(d) Synthesis of HydroxylaminoHES50/0.4

2 g of HES50/0.4 (MW=50000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 20 mL 0.1M sodium acetate buffer,pH 5.2 and 4 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 17.5 h at 22° C., the reaction mixture wasadded to 70 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v).The precipitated product was collected by centrifugation at 0° C.,washed with 30 mL of an ice-cold 1:1 mixture of acetone and ethanol(v/v), re-dissolved in 50 mL water, dialysed for 19.5 h against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized.

The molecular weight of the HES50/0.4 when measured with LALLS-GPC was56000 D and the DS was 0.41.

Example 4.1(e) Synthesis of HydroxylaminoHES18/0.4

Oxidized HES was prepared as described in DE 19628705A1. 200 mg ofoxidized

HES18/0.4 (MW=18000 D, DS=0.4) were heated at 80° C. in vaccuo for 17 hand dissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmolO-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine were added. Afterincubation for 5 d at 65° C., the reaction mixture was added to 20 mL ofice-cold 2-propanol and was incubated at −20° C. for 1 h. Theprecipitated product was collected by centrifugation at 4° C., washedwith 42 ml ice-cold 2-propanol, re-dissolved in 10 mL water, dialysedfor 27 h against water (SnakeSkin dialysis tubing, 3.5 kD cut off,Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES18/0.4 when measured with LALLS-GPC was18000 D and the DS was 0.41.

Example 4.1(f) Synthesis of HydrazidoHES10/0.4

Oxidized HES was prepared essentially as described in DE 19628705A1. 200mg of oxidized HES10/0.4 (MW=10000 D, DS=0.4, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D) were heated at 80° C. in vaccuo for17 h and dissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmol adipic dihydrazide (LancasterSynthesis GmbH, Frankfurt/Main D) were added. After incubation for 5 dat 65° C., the reaction mixture was added to 20 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was11000 D and the DS was 0.41.

Example 4.1(g) Synthesis of CarbohydrazidoHES10/0.4

Oxidized HES was prepared as described in DE 19628705A1. 200 mg ofoxidized HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were heated at 80° C. in vaccuo for 17 h anddissolved in 2 mL dry DMSO (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D). To the solution 2 mmol carbohydrazide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationfor 5 d at 65° C., the reaction mixture was added to 20 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was11000 D and the DS was 0.41.

Example 4.1(h) Synthesis of HydrazidoHES10/0.4

200 mg of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 2 mL 0.1M sodium acetatebuffer, pH 5.2. To the solution 2 mmol adipic dihydrazide (LancasterSynthesis GmbH, Frankfurt/Main D) were added. After stirring for 19 h at22° C., the reaction mixture was added to 21 mL of ice-cold 2-propanoland was incubated at −20° C. for 1 h. The precipitated product wascollected by centrifugation at 4° C., washed with 42 ml ice-cold2-propanol, re-dissolved in 10 mL water, dialysed for 27 h against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 4.1(i) Synthesis of Carbohydrazido HES10/0.4

200 mg of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 2 mL 0.1M sodium acetatebuffer, pH 5.2. To the solution 2 mmol carbohydrazide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After stirringfor 19 h at 22° C., the reaction mixture was added to 21 mL of ice-cold2-propanol and was incubated at −20° C. for 1 h. The precipitatedproduct was collected by centrifugation at 4° C., washed with 42 mlice-cold 2-propanol, re-dissolved in 10 mL water, dialysed for 27 hagainst water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 4.2 Synthesis of GM-CSF Conjugates Example 4.2(a) Oxidation ofGM-CSF

GM-CSF was purified as described in Example 8.1. Oxidation wasessentially as described in Example 8.2, followed by buffer exchange asdescribed in Example 8.3.

Example 4.2(b) Reaction of Oxidized GM-CSF of Example 4.2(a) with HESDerivatives of Examples 4.1(a)-4.1(i)

To 27 μL of a solution of oxidized GM-CSF in 0.1 M sodium acetatebuffer, pH 5.5, 3.81 μL of a solution of the HES-derivative in 0.1 Msodium acetate buffer, pH 5.5 were added and the solution was incubatedfor 16.5 h at 22° C. The following concentrations were employed:

-   (i) 78.9 mg/mL for HES derivatives prepared according to example    4.1(a), 4.1(b), 4.1(f), 4.1(g), 4.1(h) and 4.1(i)-   (ii) 395 mg/mL for HES derivatives prepared according to example    4.1(c) and 4.1(d)-   (iii) 142 mg/mL for HES derivative prepared according to example    4.1(e)

The reaction mixture was analysed by gel electrophoresis (see FIG. 8).

Example 4.3 Synthesis of GM-CSF Conjugates Example 4.3(a) Synthesis ofAldehydo-HES10/0.4 from Amino-HES10/0.4 and 4-formylbenzoic Acid

Aldehydo-HES10/0.4 was prepared according to Example 1.3(a).

Example 4.3(b) Synthesis of Aldehydo-HES10/0.4 from Amino-HES10/0.4 and4-formylbenzoic Acid

Aldehydo-HES10/0.4 was prepared according to Example 1.3(b).

Example 4.4 Synthesis of GM-CSF Conjugates by Reductive Amination withAldehyde Functionalized Hydroxyethyl Starch Synthesized According toExamples 4.3(a) and 4.3(b)

To 20 μl of a solution of GM-CSF in 0.1 M sodium acetate buffer pH 5.0(1 mg/ml) 1.91 μl of a solution of the HES-derivative (synthesized asdescribed in Examples 3.3(a) or 3.3(b)) in the same buffer (200 mg/mL)were added. The mixture was cooled to 4° C. and 4.38 μl of a 120 mMsolution of sodium cyanoborohydride in the same buffer at 4° C. wereadded and the mixture was incubated for 24 h at 4° C. The crude reactionmixture was analysed by gel electrophoresis. A successful conjugationwas observed, as indicated by the migration of the protein band tohigher molecular weight (see FIG. 9). The increased band-width is due tothe molecular weight distribution of the HES derivative used and thenumber of HES derivatives linked to the protein.

Example 5 Synthesis of AT III, IFN beta and GM-CSF Conjugates withHydroxylamino Functionalized Hydroxyethyl Starch Example 5.1 Synthesisof Hydroxylamino Functionalized Hydroxyethyl Starch

-   (a) HydroxylaminoHES10/0.4 was synthesized as described in Example    1.1(a) hereinabove.-   (b) HydroxylaminoHES50/0.7 was synthesized as described in Example    1.1(c) hereinabove.

Example 5.2 Synthesis of an IFN Beta Conjugate with HydroxylaminoHES50/0.7 According to Example 5.1(b)

To 1190 μL of a solution of oxidized IFN beta in 0.1 M sodium acetatebuffer, pH 5.5 (obtained after the step of Example 6.3), a solution of81.4 mg of hydroxylaminoHES50/0.7 in 200 μL 0.1 M sodium acetate buffer,pH 5.5 were added and the solution was incubated for 19 h at 22° C.

The reaction mixture was analysed by gel electrophoresis (see FIG. 10).

Example 5.3 Synthesis of an AT III Conjugate with HydroxylaminoHES10/0.4 According to Example 5.1(a)

To 500 μL of a solution of oxidized AT III in 0.1 M sodium acetatebuffer, pH 5.5 (obtained after the step of Example 7.3) a solution of21.6 mg of HydroxylaminoHES10/0.4 in 1500 μL 0.1 M sodium acetatebuffer, pH 5.5 were added and the solution was incubated for 20.5 h at22° C.

Example 5.4 Synthesis of a GM-CSF Conjugate with HydroxylaminoHES 10/0.4According to Example 5.1(a)

To 720 μL of a solution of oxidized GM-CSF in 0.1 M sodium acetatebuffer, pH 5.5 (obtained after the step of Example 8.3), a solution of14.0 mg of HydroxylaminoHES10/0.4 in 180 μL 0.1 M sodium acetate buffer,pH 5.5 were added and the solution was incubated for 18 h at 22° C.

Example 6 Further Characterization of Conjugates of IFN-Beta1a Example6.1(a) Purification and Analysis of Human Recombinant Interferon Beta

Recombinant human interferon beta-1a comprising identical amino acidsequence as the market products AVONEX™ (BIOGEN) and Rebif (Serono) andwas expressed from a CHO cell line transfected as described (Dittmar etal., 1989) IFN-β was purified by a three step procedure comprisingadsorption of the culture supernatant onto Blue Sepharose, elution with0.05 M Na-Phosphate buffer pH 7.0 containing 0.7 M NaCl+60% ethyleneglycol and chromatography on a 10 ml FF Zn-chelate column at ambienttemperature. The column was pre-equilibrated with 30 ml 20 mMNa-phosphate buffer, 0.3M NaCl, pH 7.4. Sample was applied after 1:2dilution with 15 ml 20 mM Na-phosphate, pH 7.2-7.5. The column was thenwashed with 25 ml 20 mM Na-phosphate, 0.3M NaCl, pH 7.4, followed byelution I (20 ml 0.1 M Na-acetate, 0.5 M NaCl, pH 5.9) and elution II(15 ml 0.1 M Na-acetate, 0.5 M NaCl, pH 4.7). Final purification wasperformed by RP-HPLC on a Vydac C4 column equilibrated in 0.1% TFA(solvent A) using a gradient from 0-100% solvent B (80% acetonitrile in0.1% TFA).

Example 6.1(b)

The IFN-beta 1a used was >95% pure (based on SDS-PAGE analysis andRP-HPLC and contained <5% of dimers (nonreducing conditions). Thecarbohydrate structures of the preparation was essentially the same asthose in AVONEX™ and showed the presence of 42% of diantennarystructures, 16% of diantennary minus proximal fucose, 12% triantennary,7% tetraantennary and 9% triantennary with 1 N-acetyllactosamine repeat(the remaining 12% were agalacto structures and small amounts of chainswith peripheral fucose). Based on HPAEC-PAD response about 14% ofoligosaccharide chains were asialo, 21% were monosialo, 35% were disialoand 19% were trisialo. Small amounts of tetrasialo structures werepresent. The vast majority of sialic acids was found asN-acetylneuraminic acid and <5% of N-glycolylneuraminic acid was presentin the preparation, therefore the preparation used resembles more theAVONEX™ market product since Rebif (Serono product) contains >15% ofN-glycolylneuraminic acid (data not shown).

Example 6.2 Periodate Oxidation of N-Acetylneuraminic Acid Residues byMild Perjodate Treatment of IFN-β1a from CHO Cells

To a 500 μg/ml solution of IFN-β (in 0.1M Na-acetate buffer pH5.5precooled and kept at 0° C.) was added an ice-cold solution of 10 mMNatrium-meta-periodate resulting in a final concentration of 1 mMNatrium-meta-periodate. The mixture was incubated at 0° C. for 1 hour inan ice-bath in the dark and the reaction was terminated by addition of20 μl of glycerol and incubated for further 5 minutes. SubsequentlyIFN-β samples were concentrated using a Vivaspin concentrator unit asdescribed below.

Example 6.3 Buffer Exchange of Perjodate Oxidised IFN-β1a for SubsequentHesylation

Buffer exchange was performed using 0.5 ml Vivaspin 2 concentrator units(Vivaspin AG, Hannover, Germany) with a polyethersulfone (PES) membraneand a 10 Kda cut-off First, the concentrator unit was washed by additionof 0.5 ml of 0.1 M Na-acetate buffer pH 5.5 and centrifugation at 4000rpm at 6° C. in a Megafuge 1.0R (Kendro Laboratory Equipment, Osterode,Germany). Subsequently, 0.5 ml of the periodate oxidised IFN-β solutionwas added to the concentrator unit and was centrifuged at 4000 rpm for25 min until an at least 5-fold concentration was achieved. 0.1 MNa-acetate buffer pH 5.5 was added to the concentrate to a final volumeof 0.5 ml which was centrifuged as described above. The centrifugationcycle was repeated 3 times, the final concentrate was removed andtransferred into a 2 ml plastic vial (Eppendorff, Germany) and kept onice until further use in the HAS-modification reaction.

Example 6.4 Synthesis of Conjugates of HAS and IFN-β

Synthesis was carried out as described in Example 5.2 above.

Example 6.5 Separation of HESylated IFN-β and Excess HAS Derivativesfrom Incubations of the Periodate-Oxidized Protein withHydroxylamino-HES 50/0.7.

Summary: RP-HPLC Runs were performed at room temperature using an AKTAexplorer 10 equipment and flow rate of 1.25 ml/min. Aliquots of theincubation mixtures containing 400 μg IFN-β were applied onto a 250mm×10 mm C₁₈-phase column equilibrated with 1.25 CV of 11% Solvent B(0.1% TFA, 90% acetonitrile) and 89% Solvent A (0.1% TFA). The samples(ca. 1.25 ml) were then injected and the sample loop was washed with 11ml of 11% solvent B. Following washing of the column with 0.2 CV of 11%solvent B, a linear gradient from 11% to 90% solvent B over 2 CV wasapplied. Elution of the column was continued by using 0.8 CV of 90%solvent B, and finally the column was re-equilibrated with 1.0 CV of 11%Solvent B.

The IFN-β proteins eluted in a volume of 7.5 ml at a concentration of62% solvent B. The recovery of the protein was 60% (HES IFN-β CHO) basedon the specific peak area of 790 mAU×ml×mg⁻¹ that was obtained with astandard IFN-β preparation on a C₄-phase column by using the sameequipment.

Materials and Methods for Example 6.5

Equipment and Materials

Equipment: ÄKTA explorer 10 (Amersham Pharmacia Biotech), with: PumpP-903 Mixer M-925, with 0.6 ml chamber Monitor UV-900, with 10 mm flowcell Monitor pH/C-900 Fraction Collector Frac-900 Sample loop 2 mlSoftware Unicorn Version 3.21 Column: 250 mm × 10 mm, Macherey-Nagel250-½″- 10 Nucleosil 7 C18, Cat. No. 715002, Lot-No. 4020854 Columnvolume: 20 ml Flow rate: 1.25 ml/min Solvent A: 0.1% TFA in HPLC-waterSolvent B: 90% acetonitrile, 0.1% TFA in HPLC-water

Method for the RP-HPLC Run of Example 6.5

Volume Step Solvent A Solvent B 0.25 CV Equilibration 89% 11% 11 mlSample injection 89% 11% Fractionation 89% 11% 0.20 CV Wash out unboundsample 89% 11% 2.00 CV Linear gradient 89-10%   11-90%   0.80 CVIsocratic 10% 90% End Fractionation 10% 90% 1.00 CV Re-equilibration 89%11% Detection: A 280 nm A 221 nm A 206 nm Conductivity Fractionation:1.25 ml/fraction

Example 6.6 Analytical Experiments Example 6.6(a) Liberation of N-LinkedOligosaccharides with Recombinant Polypeptide N-Glycosidase (Roche,Penzberg, Germany)

To 100-120 μg of native, periodated oxidised or HAS-modified IFN-β1a in50 mM Na-phosphate buffer pH 7.2 were added 25 μl of recombinantpolypeptide N-glycosidase (Roche, Penzberg, Germany; 250 units/250 μllot: 101610420). The reaction mixture was incubated at 37° C. for 12-18hours and the release of N-glycosidically bound oligosaccharides waschecked by SDS-PAGE analysis of 3-5 μg protein under reducing conditionsand subsequent staining of protein bands with Coomassie Blue (Carl RothGmbH Karlsruhe, Germany) and detection of the specific shift of theIFN-beta protein band to the migration position of the de-N-glycosylatedform.

Example 6.6(b)

The released N-glycans were separated from the polypeptide by additionof 3 volumes of −20° C. 100% ethanol and incubation at −20° C. wasperformed for at least 2 hours. The precipitated protein was removed bycentrifugation at 13,000 rpm for 10 minutes at 4° C. The pellet was thensubjected to two additional washes with 500 μl ice-cold 70% ethanol. Theoligosaccharides in the pooled supernatants were dried in a vacuumcentrifuge (Speed Vac concentrator, Savant Instruments Inc., USA). Theglycan samples were desalted using Hypercarb cartridges (100 or 200 mg)as follows: prior to use, the cartridges were washed three times with500 μl 80% (v/v) acetonitrile in 0.1% (v/v) TFA followed by three washeswith 500 μl water. The samples were diluted with water to a final volumeof at least 300 μl before loading onto the cartridges. They wererigorously washed with water. Oligosaccharides were eluted with 1.2 ml25% acetonitrile containing 0.1% (v/v) TFA. The eluted oligosaccharideswere neutralised with 2 M NH₄OH and were dried in a Speed Vacconcentrator. They were stored at −20° C. in H₂O.

Example 6.6(c) Mild Acid Hydrolysis

Mild acid hydrolysis of oligosaccharides (liberation of sialic acids andHAS-modified sialic acid derivatives from N-glycans) was performed asfollows: aliquots of the desalted oligosaccharides or HAS-modifiedoligosaccharides were mixed with the same volume of 10 mM H₂SO₄ and wereincubated for 90 minutes at 80° C. After neutralisation with 50 mM NaOHthe desialylated glycan mixture was dried in a speed-vac concentratorand was adjusted to an appropriate concentration for analysis inHPAEC-PAD (high-pH-anion exchange chromatography with pulsedamperometric detection). For subsequent MALDI/TOF MS analysis of neutraloligosacharide samples (0.05-1 nmol) were desalted using small Hypercarbcolumns prepared by adding 25-40 μl of graphitisized carbon into 200 μlpipet tips.

Example 6.6(d) Oligosaccharide Mapping by HPAEC-PAD (High-pH-AnionExchange Chromatography with Pulsed Amperometric Detection)

BioLC System, (Dionex, Sunnyvale) consisting of a AS50 Autosampler, AS50Thermal Compartment, ED50 Electrochemical Detector, GS50 Gradient Pump,Software Chromeleon Chromatography Management System, was used alongwith a CarboPac PA-100 separation column (4×250 mm) and a CarboPacPA-100 pre-column (4×50 mm). Two different modes were used for themapping and for quantitation of oligosaccharides.

I) Asialo-Mode:

Neutral oligosaccharides were subjected to HPAEC-PAD mapping using agradient of solvent A (200 mM NaOH) and solvent B (200 mM NaOH plus 600mM Na-acetate) as depicted in the following table:

TABLE Gradient for mapping of neutral oligosacharides Time [min] solventA [%] solvent B [%] 0 100 0 5 100 0 35 80 20 45 70 30 47 0 100 52 0 10053 100 0 60 100 0 Flow rate: 1 ml/min

The detector potentials for the electrochemical detector were:

TABLE Detector-Potentials for oligosaccharides Time [ms] potential [mV]0 50 200 50 400 50 410 750 600 750 610 −150 1000 −150

II) Oligos-Mode:

Native oligosaccharides were subjected to HPAEC-PAD mapping using agradient of solvent C (100 mM NaOH) and solvent D (100 mM NaOH plus 600mM Na-acetate) as depicted in the following table:

TABLE Gradient mapping of native (sialylated) oligosaccharides Time[min] solvent C [%] solvent D [%] 0 100 0 2 100 0 50 65 35 60 0 100 63 0100 64 100 0 70 100 0 Flow rate: 1 ml/minThe detector potentials for the electrochemical detector were:

TABLE Detector-Potentials for oligosaccharides Time [ms] potential [mV]0 50 200 50 400 50 410 750 600 750 610 −150 1000 −150

The specific peak areas (nC×min×nmol⁻¹) were calculated using responsefactors obtained with defined oligosaccharide standards (disialylateddiantennary, trisialylated triantennary, and tetrasialylatedtetraantennary structures with and without N-acetyllactosamine repeats(Nimtz et al., 1993, Schroeter et al., 1999, Grabenhorst et al., 1999).

Results for HAS-Modified IFN-β

Upon RP-HPLC on C-18 phase HAS-modified IFN-β was detected in fractions32-37. The recovery of HAS-IFN-β was calculated.

The arrow in FIG. 11 indicates the migration position of unmodifiedIFN-β presumably due to forms lacking terminal sialic acid derivativeswhereas the HAS modified IFN-β was detected as a broad diffuse Coomassiestained area spanning molecular masses of 35 Kda-120 Kda.

Fractions 32-37 from the RP-HPLC eluate were pooled and concentrated ina speed Vac concentrator after neutralisation. Typically, 100-200 μgaliquots of the IFN-β sample were dried and dissolved in 50 mMNa-phosphate pH 7.2 plus 0.05% Tween-20 and was incubated withpolypeptide N-glycosidase for 20-30 hours at 37° C. The resultingoligosaccharides were subjected to HPAEC-PAD analysis (Example 6.6d)before and after mild acid treatment.

As depicted in FIG. 12, the oligosaccharide material from HAS-modifiedIFN-β eluted after 52 minutes from the column under conditions where theasialo, mono-, di- and trisialylated were detected at 16-20 min, 21-26min, 28-33 min and 34-38 min, respectively. After mild acid treatment ofthe oligosacharide sample under conditions where complete liberation ofsialic acids is achieved, the expected neutral complex-type N-glycans ofIFN-β were detected in the HPAEC-PAD profile and the releasedHAS-derivative was detected at a retention time of 46-49 min (usinggradient Asialo-mode, see Example 6.6 dI) this indicates that HAS isattached to the N-linked oligosaccharides of IFN-β via a acid labilelinkage as is expected (FIG. 13).

Example 7 Further Characterization of Conjugates of AT III Example 7.1Human AT III

AT III used was recombinant human AT III (ATryn® from GTCBiotherapeutics).

Example 7.2 Periodate Oxidation of N-acetylneuraminic Acid Residues byMild Perjodate Treatment of AT III

Periodate oxidation was carried out essentially as described forIFN-beta in Example 6.2.

Example 7.3 Buffer Exchange of Perjodate Oxidised AT III for SubsequentHesylation

Buffer exchange was carried out essentially as described for IFN-beta inExample 6.3.

Example 7.4 Synthesis of Conjugates of HAS and AT III

Synthesis was as described in Example 5.3. above.

Example 7.5 AT III Ion Exchange Chromatography for Separation ofHAS-Modified AT III from Excess HAS-Reagent

7.5.1. Buffer exchange of antithrombin III samples for subsequentpurification by ion-exchange chromatography was performed using Vivaspinconcentrators (10.000

MW CO PES, Vivascience Cat. No. VS0602, Lot-No. 03VS0633). Samples fromHAS-modification reactions (2 mg AT III in 1.6 ml) were diluted to 5 mlwith buffer A (20 mM N-morpholio-propane sulfonic acid adjusted to pH8.0 with NaOH, MOPS). Samples were spun down according to manufacturer'srecommendations to approximately 0.4-0.6 ml and thedilution/concentration step was repeated twice. Finally, protein sampleswere washed out of the concentrator unit.

7.5.2. The purification of the AT III sample was performed at ambienttemperature using an AKTA explorer 10 system (Amersham PharmaciaBiotech) consisting of a Pump P-903, Mixer M-925, with a 0.6 ml chamber,a monitor UV-900 along with a 10 mm flow cell was used, a monitorpH/C-900, a sample pump P-950 and a 5 ml sample loop. The AKTA systemwas run under the Software Unicorn Version 3.21. The incubation mixturein buffer A (20 mM MOPS, pH 8.0) was applied at a flow rate of 0.6ml/min to a column containing 2 ml Q-Sepharose Fast Flow (Amersham, codeno. 17-0510-01, lot no. 254665) column (Amersham Biosciences C 10/10)equilibrated with 6 CV of buffer A at a flow rate of 1 ml/min. Thecolumn was washed with 6 CV of buffer A at a flow rate of 0.8 ml/min andelution was performed by using 4 CV of buffer B (0.5 M NaCl in 20 mMNa-phosphate, pH 6.5) at a flow rate of 0.6 ml/min. The column wasregenerated by using 4 CV of buffer C (1.5 M NaCl in 20 mM Na-phosphate,pH 6.5) at a flow rate of 0.6 ml/min and re-equilibrated with buffer A.The AT III protein was eluted from the column in a volume ofapproximately 4 ml.

Method

Volume Step Buffer Flow rate 1 CV Equilibration 100% buffer A 1.0 ml/minStart Fractionation 100% buffer A 1.0 ml/min 10 ml Load sample sample inbuffer A 0.6 ml/min 6 CV Wash out unbound sample 100% buffer A 0.8ml/min 4 CV Elution 100% buffer B 0.6 ml/min 4 CV Regeneration (Elution2) 100% buffer C 0.6 ml/min Stop Fractionation 100% buffer C 0.6 ml/min5 CV Reequilibration 100% buffer A 1.0 ml/min

Buffer A: 20 mM MOPS/NaOH pH 8.0; Buffer B: 20 mM Na-phosphate, 0.5 MNaCl, pH 6.5; Buffer C: 20 mM Na-phosphate, 1.5 M NaCl, pH 6.5. Proteinelution was detected at A280 nm and 1 ml fractions were collected.

Example 7.6 Analytical Experiments Example 7.6(a) Liberation ofN-Glycans from Unmodified, Periodate Oxidised and HAS Modified AT IIISamples was Performed with Recombinant

300-600 μg of AT III samples were reduced in the presence of 5 mMdithioerythreitol for 10 min at 90° C. at pH 8.1 in the presence of 0.6%SDS, thereafter NP 40 was added to a final concentration of 0.6%. To0.3-0.6 mg of native, periodate oxidised or HAS-modified AT III in 50 mMNa-phosphate buffer pH 7.2 were added 40 μl of recombinant polypeptideN-glycosidase (Roche, Penzberg, Germany; 250 units/250 μl lot:101610420). The reaction mixture was incubated at 37° C. for 12-18 hoursand the release of N-glycosidically bound oligosaccharides was checkedby SDS-PAGE analysis of 5-10 μg protein under reducing conditions andsubsequent staining of protein bands with Coomassie Blue (Carl Roth GmbHKarlsruhe, Germany) and detection of the specific shift of the AT IIIprotein band to the migration position of the de-N-glycosylated proteinform.

Example 7.6(b)

The released N-glycans were separated from the polypeptide by additionof 3 volumes of −20° C. 100% ethanol and incubation at −20° C. wasperformed for at least 2 hours. The precipitated protein was removed bycentrifugation at 13,000 rpm for 10 minutes at 4° C. The pellet was thensubjected to two additional washes with 500 μl ice-cold 70% ethanol. Theoligosaccharides in the pooled supernatants were dried in a vacuumcentrifuge (Speed Vac concentrator, Savant Instruments Inc., USA). Theglycan samples were desalted using Hypercarb cartridges (100 or 200 mg)as follows: prior to use, the cartridges were washed three times with500 μl 80% (v/v) acetonitrile in 0.1% (v/v) TFA followed by three washeswith 500 μl water. The samples were diluted with water to a final volumeof at least 300 μl before loading onto the cartridges. They wererigorously washed with water. Oligosaccharides were eluted with 1.2 ml25% acetonitrile containing 0.1% (v/v) TFA. The eluted oligosaccharideswere neutralised with 2 M NH₄OH and were dried in a Speed Vacconcentrator. They were stored at −20° C. in H₂O.

Example 7.6(c) Mild Acid Hydrolysis

Mild acid hydrolysis of oligosaccharides (liberation of sialic acids andHAS-modified sialic acid derivatives from N-glycans) was performed asfollows: aliquots of the desalted oligosaccharides or HAS-modifiedoligosaccharides were mixed with the same volume of 10 mM H₂SO₄ and wereincubated for 90 minutes at 80° C. After neutralisation with 50 mM NaOHthe desialylated glycan mixture was dried in a speed-vac concentratorand was adjusted to an appropriate concentration for analysis inHPAEC-PAD (high-pH-anion exchange chromatography with pulsedamperometric detection). For subsequent MALDI/TOF MS analysisi ofneutral oligosacharide samples (0.05-1 nmol) were desalted using smallHypercarb columns prepared by adding 25-40 μl of graphitisized carboninto 200 μl pipet tips.

Example 7.6(d) Oligosaccharide Mapping by HPAEC-PAD (High-pH-AnionExchange Chromatography with Pulsed Amperometric Detection)

A BioLC System, (Dionex, Sunnyvale) consisting of a AS50 Autosampler,AS50 Thermal Compartment, ED50 Electrochemical Detector, GS50 GradientPump, Software Chromeleon Chromatography Management System, was usedalong with a CarboPac PA-100 separation column (4×250 mm) and a CarboPacPA-100 pre-column (4×50 mm). Two different modes were used for themapping and for quantitation of oligosaccharides.

I) Asialo-Mode:

Neutral oligosaccharides were subjected to HPAEC-PAD mapping using agradient of solvent A (200 mM NaOH) and solvent B (200 mM NaOH plus 600mM Na-acetate) as depicted in the following table:

TABLE Gradient for mapping of neutral oligosacharides Time [min] solventA [%] solvent B [%] 0 100 0 5 100 0 35 80 20 45 70 30 47 0 100 52 0 10053 100 0 60 100 0 Flow rate: 1 ml/minThe detector potentials for the electrochemical detector were

TABLE Detector-Potentials for oligosaccharides Time [ms] potential [mV]0 50 200 50 400 50 410 750 600 750 610 −150 1000 −150

II) Oligos-Mode:

Native oligosaccharides were subjected to HPAEC-PAD mapping using agradient of solvent C (100 mM NaOH) and solvent D (100 mM NaOH plus 600mM Na-acetate) as depicted in the following table:

TABLE Gradient mapping of native (sialylated) oligosaccharides Time[min] solvent C [%] solvent D [%] 0 100 0 2 100 0 50 65 35 60 0 100 63 0100 64 100 0 70 100 0 Flow rate: 1 ml/minThe detector potentials for the electrochemical detector were:

TABLE Detector-Potentials for oligosaccharides Time [ms] potential [mV]0 50 200 50 400 50 410 750 600 750 610 −150 1000 −150

The specific peak areas (nC×min×nmol⁻¹) were calculated using responsefactors obtained with defined oligosaccharide standards (disialylateddiantennary, trisialylated triantennary, and tetrasialylatedtetraantennary structures with and without N-acetyllactosamine repeatscontaining proximal fucose (Nimtz et al., 1993, Schroeter et al., 1999,Grabenhorst et al., 1999).

Results

HAS modification of AT III resulted in a significant molecular massshift in SDS-PAGE indicating covalent attachment of HAS to the protein(see FIG. 14 a.)

Ion exchange chromatography of the AT III subjected to HAS modificationafforded an AT III fraction (>85% recovery based on comparison withuntreated AT IIII).

De-N-glycosylation of the untreated AT III, the periodate treated ATIIII and the HAS-modified AT-III obtained after anion exchange onQ-Sepharose resulted in a comparable molecular weight shift in SDS-PAGEas depicted in FIG. 14B.

The liberated N-glycans of the AT III samples were isolated by adsobtionto and elution from Hypercarb cartridges and subjected to HPAEC-PADanalysis. The native N-glycans from HAS-modified AT III revealed thepresence of all neutral oligosaccharide peaks detected in controlsamples (see trace 1 in FIG. 15). Upon mild acid treatment, all threeN-glycan preparations showed a very similar pattern of the neutraloligosaccharides indicating the acid labile nature of theHAS-modification which is compatible with HAS-modification at the sialicacid derivatives of the oligosaccharides (cf. FIG. 16). Thecomparability of the desialylated structures was confirmed by MALDI/TOFanalysis (data not shown).

Example 8 Further Characterization of Conjugates of GM-CSF Example 8.1Description of GM-CSF

Human recombinant GM-CSF was prepared after expression from CHO K1 cellsessentially as described by Forno et al., 2004, (Guillermina Forno,Mariela Bollati Fogolin, Marcos Oggero, Ricardo Kratje, MarinaEtcheverrigaray, Harald S. Conradt, Manfred Nimtz (2004) N- and O-linkedcarbohydrates and glycosylation site occupancy in recombinant humangranulocyte-macrophage colony-stimulating factor secreted by a Chinesehamster ovary cell line; Eur J Biochem, 271 (5),907-919), and had thecarbohydrate structures described therein.

The recombinant GM-CSF can also be purified by conventionalchromatographic steps e.g. as described in: Okamoto, M., Nakai, M.,Nakayama, C., Yanagi, H., Matsui, H., Noguchi, H., Namiki, M., Sakai,J., Kadota, K., Fukui, M. & Hara, H. (1991) Purification andcharacterization of three forms of differently glycosylated recombinanthuman Granulocyte-Macrophage Colony-Stimulating Factor. Archives ofBiochemistry and Biophysics 286, 562-568.

Amino acid sequence of human GM-CSF used in this study:

(SEQ ID NO: 1) APA RSPSPSTQPW EHVNAIQEAR RLLNLSRDTA AEMNETVEVISEMFDLQEPT CLQTRLELYK QGLRGSLTKL KGPLTMMASHYKQHCPPTPE TSCATQIITF ESFKENLKDF LLVIPFDCWE PVQE.(according to reference Forno et al., supra)

Example 8.2 Periodate Oxidation of N-acetylaneuraminic Acid Residues byMild Perjodate Treatment of Recombinant GM-CSF

To a 0.80 mg/ml solution of GM-CSF in 0.1M Na-acetate pH 5.5 kept at 0°C. were added an ice-cold solution of 10 mM Natrium-meta-periodateresulting in a final concentration of 1 mM Natrium-meta-perjodate. Themixture was incubated at 0° C. for 1 hour in an ice-bath in the dark andthe reaction was terminated by addition of 20 μl of glycerol andincubated for further 5 minutes.

Example 8.3 Buffer Exchange of Perjodate Oxidised GM-CSF for SubsequentHAS-Modification

Buffer exchange was performed using a 5 ml Vivaspin 6 concentrator(Vivaspin AG, Hannover, Germany) with a polyethersulfone (PES) membrane.The concentrator unit was washed by addition of 5 ml of 0.1 M Na-acetatebuffer pH 5.5 and centrifugation of the concentrator unit at 4000 rpm at6° C. in a Megafuge 1.0R (Kendro Laboratory Equipment, Osterode,Germany). Subsequently, 1-5 ml of the perjodate oxidised GM-CSF solutionwas added to the concentrator unit and was centrifuged at 4000 rpm for25 min until a 5-fold concentration was achieved. 4 ml of 0.1 MNa-acetate buffer pH 5.5 was added to the concentrate which wascentrifuged as described above. The centrifugation cycle was repeated 3times, the final concentrate was removed and transferred into a 2.0 mlplastic vial, after washing of the concentrator unit 2 times with each150 μl of Na-acetate buffer pH 5.5; the volume of the protein wasadjusted with Na-acetate buffer pH 5.5 to

Example 8.4 Synthesis of Conjugates of HAS and GM-CSF

Synthesis was as described in Example 5.4. above.

Example 8.5 Purification of GM-CSF After HAS-Modification

Separation of HAS-modified GM-CSF from excess activated HES derivativesfrom incubations of the periodate-oxidized protein withHydroxylamino-HES 10/0.7.

Summary: Runs were performed at room temperature using an ÄKTA explorer10 equipment and flow rate of 1.25 ml/min. Aliquots of the incubationmixtures with 400 μg IFN-β were applied onto a 250 mm×10 mm C₁₈-phasecolumn equilibrated with 1.25 CV of 11% Eluent B (0.1% TFA, 90%acetonitrile) and 89% Eluent A (0.1% TFA). The samples (ca. 1.25 ml)were then injected and the sample loop was washed with 11 ml of 11%Eluent B. Following washing of the column with 0.2 CV of 11% Eluent B, alinear gradient from 11% to 90% Eluent B over 2 CV was applied. Elutionof the column was continued by using 0.8 CV of 90% Eluent B, and finallythe column was re-equilibrated with 1.0 CV of 11% Eluent B.

The GM-CSF protein eluted in a volume of 7.5 ml at a concentration of %Eluent B. The recovery of the protein was 60% (HES GM-CSF) based on astandard GM-CSF preparation run on the column by using the samegradient.

Materials and Methods for Example 8.5

Equipment and Materials

Equipment: ÄKTA explorer 10 (Amersham Pharmacia Biotech), with: PumpP-903 Mixer M-925, with 0.6 ml chamber Monitor UV-900, with 10 mm flowcell Monitor pH/C-900 Fraction Collector Frac-900 Sample loop 2 mlSoftware Unicorn Version 3.21 Column: 250 mm × 10 mm, Macherey-Nagel250-½″- 10 Nucleosil 7 C₁₈, Cat. No. 715002, Lot-No. 4020854 Columnvolume: 20 ml Flow rate: 1.25 ml/min Solvent A: 0.1% TFA in HPLC-waterSolvent B: 90% acetonitrile, 0.1% TFA in HPLC-grade water

Method for the RP-HPLC run of Example 8.5

Volume Step solvent A solvent B 0.25 CV Equilibration 89% 11% 11 mlSample injection 89% 11% Fractionation 89% 11% 0.20 CV Wash out unboundsample 89% 11% 2.00 CV Linear gradient 89-10%   11-90%   0.80 CVIsocratic 10% 90% End Fractionation 10% 90% 1.00 CV Re-equilibration 89%11% Detection: 280 nm 221 nm 206 nm Conductivity Fraction volume: 1.25ml/fractionResults from Example 8.5

RP-HPLC separation of GM-CSF (Example 8.5) from excess HAS(10Kda)-derivative afforded fractions 26-32 which contained all of theHAS-modified GM-CSF eluting from the column. The SDS-PAGE pattern of theprotein after HAS modification showed a broad diffuse band in themolecular mass region between 35-90 Kda, whereas the unmodified GM-CSFshowed the pattern of the nonglycosylated, mono-N-glycosylated anddi-N-glycosylated forms (FIG. 17, cf. reference Forno et. al., 2004).

Example 8.6 Analytical Experiments

a) Liberation of N-Linked Oligosaccharides with Recombinant PolypeptideN-Glycosidase

To 200 μg-1 mg of native, periodated oxidised or HAS-modified GM-CSF in50 mM Na-phosphate buffer pH 7.2 were added 25 μl of recombinantpolypeptide N-glycosidase (Roche, Penzberg, Germany; 250 units/250 μllot: 101610420). The reaction mixture was incubated at 37° C. for 12-18hours and the release of N-glycosidically bound oligosaccharides waschecked by SDS-PAGE analysis of 5-10 μg protein under reducingconditions and subsequent staining of protein bands with Coomassie Blue(Carl Roth GmbH Karlsruhe, Germany) and detetection of the shift of theGM-CSF protein band to the migration position of the de-N-glycosylatedprotein forms (cf. FIG. 18).

b) Isolation and Desalting of Enzymatically Released N-Glycans andHAS-Modified N-Glycans

The released N-glycans were separated from the polypeptide by additionof 3 volumes of cold 100% ethanol and incubation at −20° C. for at least2 hours. The precipitated protein was removed by centrifugation at13,000 rpm for 10 minutes at 4° C. The pellet was then subjected to twoadditional washes with 500 μl ice-cold 70% ethanol. The oligosaccharidesin the pooled supernatants were dried in a vacuum centrifuge (Speed Vacconcentrator, Savant Instruments Inc., USA). The glycan samples weredesalted using Hypercarb cartridges (100 or 200 mg) as follows: prior touse, the cartridges were washed three times with 500 μl 80% (v/v)acetonitrile in 0.1% (v/v) TFA followed by three washes with 500 μlwater. The samples were diluted with water to a final volume of at least300 μl before loading onto the cartridges. They were then rigorouslywashed with water 83 cartridge volumes). Oligosaccharides were elutedwith 1.2 ml 25% acetonitrile containing 0.1% (v/v) TFA. The elutedoligosaccharides were neutralised with 2 M NH₄OH and were dried in aSpeed Vac concentrator. They were stored at −20° C. in H₂O until furtheruse.

c) Mild Acid Hydrolysis of Oligosaccharides (Removal of Sialic Acids andHAS-Modified Sialic Acid Deivatives from Oligosacharides)

Aliquots of the desalted oligosaccharides were mixed with the samevolume of 10 mM H₂SO₄ and were incubated for 90 minutes at 80° C. Afterneutralisation with 50 mM NaOH the desialylated glycans were dried in aspeed-vac and were adjusted to an appropriate concentration for analysisin HPAEC-PAD (high-pH-anion exchange chromatography with pulsedamperometric detection). For MALDI/TOF-MS analysis neutral N-glycanswere desalted using pipette tips containing 20-30 μl of Hypercarbmaterial for adsorption, washing and elution with 25% acetonitrile in0.1% trifluoro acetic acid in H₂O.

d) Oligosaccharide Mapping by HPAEC-PAD (High-pH-Anion ExchangeChromatography with Pulsed Amperometric Detection)

Mapping and for quantitation of oligosaccharides was carried outessentially as described in Example 7.6.d).

Results

RP-HPLC purified material from Example 8.5 was used to demonstratemodification of the protein with HAS-derivatives at its carbohydratechain via oxidised sialic acids. Monosaccharide compositional analysisby gas chromatographic analysis of their trimethylsialylated derivativesrevealed the presence of glucose and the mono and di-hydroxyethylatedglucose derivatives as well as mannose, galactose andN-acetylglucosamine and small amounts of N-acetylgalactosamine.

The HPAEC-PAD analysis of the native oligosaccharides liberated from theHAS-modified GM-CSF revealed a peak corresponding to HAS modification ofthe complex-type oligosaccharides (see FIG. 19).

Upon mild acid treatment the neutral N-glycans of GM-CSF were detectedin the sample of the HAS-modified protein and also the modifiedHAS-derivative eluting at 47-49 minutes.

Example 9 Synthesis of ATIII-Conjugates Example 9.1 Synthesis ofHydroxylamino-HES Derivatives Example 9.1(a) Synthesis ofHydroxylaminoHES10/0.4

0.8 g of HES10/0.4 (MW=10000 D, DS=0.4, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 8 mL 0.1M sodium acetatebuffer, pH 5.5 and 8 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl aminewere added. After shaking for 19 h at 22° C., the reaction mixture wasadded to 40 mL of 2-propanol at −20° C. The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 50 mL water,dialysed for 45 h against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theisolated product yield was 73%.

The molecular weight of the HES10/0.4 when measured with LALLS-GPC was8500 D and the DS was 0.41.

Example 9.1(b) Synthesis of HydroxylaminoHES10/0.7

1.06 g of HES10/0.7 (MW=10000 D, DS=0.7, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 10 mL 0.1M sodium acetatebuffer, pH 5.5 and 10.9 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxylamine were added. After shaking for 19 h at 22° C., the reaction mixturewas added to 40 mL of 2-propanol at −20° C. The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 50 mL water,dialysed for 45 h against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theisolated product yield was 60%.

The molecular weight of the HES10/0.7 when measured with LALLS-GPC was10500 D and the DS was 0.76.

Example 9.1(c) Synthesis of HydroxylaminoHES30/0.4

2 g of HES30/0.4 (MW=30000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 18 mL 0.1M sodium acetate buffer,pH 5.5 and 6.67 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 15.5 h at 22° C., the reaction mixture wasadded to 80 mL of 2-propanol at −20° C. The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 50 mL water,dialysed for 45 h against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theisolated product yield was 83%.

The molecular weight of the HES30/0.4 when measured with LALLS-GPC was33000 D and the DS was 0.41.

Example 9.1(d) Synthesis of HydroxylaminoHES30/0.7

2 g of HES30/0.7 (MW=30000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 18 mL 0.1M sodium acetate buffer,pH 5.5 and 6.67 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 15 h at 22° C., the reaction mixture was addedto 80 mL of 2-propanol at −20° C. The precipitated product was collectedby centrifugation at 4° C., re-dissolved in 50 mL water, dialysed for 45h against water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized. The isolatedproduct yield was 86%.

The molecular weight of the HES30/0.7 when measured with LALLS-GPC was31000 D and the DS was 0.76.

Example 9.1(e) Synthesis of HydroxylaminoHES50/0.4

2 g of HES50/0.4 (MW=50000 D, DS=0.4, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 20 mL 0.1M sodium acetate buffer,pH 5.5 and 4 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19.5 h at 22° C., the reaction mixture wasadded to 80 mL of 2-propanol at −20° C. The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 50 mL water,dialysed for 45 h against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theisolated product yield was 94%.

The molecular weight of the HES50/0.4 when measured with LALLS-GPC was56000 D and the DS was 0.41.

Example 9.1(f) Synthesis of HydroxylaminoHES50/0.7

2.5 g of HES50/0.7 (MW=50000 D, DS=0.7, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were dissolved in 25 mL 0.1M sodium acetatebuffer, pH 5.5 and 5 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl aminewere added. After shaking for 19.5 h at 22° C., the reaction mixture wasadded to 80 mL of 2-propanol at −20° C. The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 50 mL water,dialysed for 45 h against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theisolated product yield was 85%.

The molecular weight of the HES50/0.7 when measured with LALLS-GPC was47000 D and the DS was 0.76.

Example 9.1(g) Synthesis of HydroxylaminoHES10/0.7

2 g of HES10/0.7 (MW=10000 D, DS=0.7, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 18 mL 0.1M sodium acetate buffer,pH 5.2 and 20 mmol O-[2-(2-aminooxy-ethoxy)-ethyl]-hydroxyl amine wereadded. After shaking for 19 h at 22° C., the reaction mixture was addedto 100 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 21 h against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized. The isolated product yield was not determined.

The molecular weight of the HES10/0.7 when measured with LALLS-GPC was10500 D and the DS was 0.76.

Example 9.2 Synthesis of Aldehydo-HES Derivatives Example 9.2(a)Synthesis of AminoHES10/0.7

6.02 g of oxo-HES10/0.7 (MW=10000 D, DS=0.7, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D, prepared according to DE 196 28 705A1) were dissolved under nitrogen in 32 mL dry dimethyl sulphoxide(Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 6.03 ml of1,4-diaminobutane were added. After stirring at 40° C. for 17 h thereaction mixture was added to 150 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., washed with 40 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v) and collected by centrifugation. The crudeproduct was dissolved in 80 ml water, dialysed for 4 d against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The isolated product yield was 52%.

The molecular weight of the HES10/0.7 when measured with LALLS-GPC was15000 D and the DS was 0.76.

Example 9.2(b) Synthesis of AldehydoHES10/0.7

150 mg 4-formylbenzoic acid and 230 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 10mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 204 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 1 g of aminoHES10/0.7 (synthesised as described in9.2(a)) were added. After shaking for 19 h at 22° C., the reactionmixture was added to 84 mL of an ice-cold 1:1 mixture of acetone andethanol (v/v). The precipitated product was collected by centrifugationat 4° C., re-dissolved in 50 mL water, dialysed for 2 d against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The isolated product yield was 83%.

Example 9.2(c) Synthesis of AminoHES50/0.7

6.09 g of oxo-HES 50/0.7 (MW=50000 D, DS=0.7, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D prepared according to DE 198 26 705 A1with adaptation of the molar ratios of the ingredients) were dissolvedunder nitrogen in 32 mL dry dimethyl sulphoxide (Fluka, Sigma-AldrichChemie GmbH, Taufkirchen, D) and 1.22 ml of 1,4-diaminobutane wereadded. After stirring at 40° C. for 17 h the reaction mixture was addedto 150 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C., washedwith 40 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v) andcollected by centrifugation. The crude product was dissolved in 80 mlwater, dialysed for 4 d against water (SnakeSkin dialysis tubing, 3.5 kDcut off, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theisolated product yield was 67%.

The molecular weight of the HES50/0.7 when measured with LALLS-GPC was57000 D and the DS was 0.76.

Example 9.2(d) Synthesis of AldehydoHES50/0.7

124 mg 4-formylbenzoic acid and 174 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 38mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 155 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 3.8 g of aminoHES50/0.7 (synthesised as describedin 9.2(c)) were added. After shaking for 19 h at 22° C., the reactionmixture was added to 160 mL of an ice-cold 1:1 mixture of acetone andethanol (v/v). The precipitated product was collected by centrifugationat 4° C., re-dissolved in 20 mL N,N-dimethylformamide and precipitatedwith 80 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v) asdescribed above. After centrifugation, the precipitate was dissolved in50 mL water, dialysed for 2 d against water (SnakeSkin dialysis tubing,3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn, D) andlyophilized. The isolated product yield was 77%.

Example 9.3 Synthesis of the ATIII-Conjugates by the Glycan StrategyExample 9.3(a) Reaction of Oxidized ATIII with Reaction Products ofExamples 9.1(a)-9.1(g)

To 685 μL of a solution of oxidized ATIII in 0.1 M sodium acetatebuffer, pH 5.5 (GlycoThera, B52 perj-ox STM 112-366, 4.375 mg/ml, seeexample 3.2.), 814 μL 0.1 M sodium acetate buffer, pH 5.5 and 1.5 mL ofa solution of the HES-derivative in 0.1 M sodium acetate buffer, pH 5.5were added and the solution was incubated for 26 h at 22° C.

The following final HES concentrations were employed:

0.46 mg/mL for HES derivatives prepared according to example 9.1(a) and9.1(b).

1.38 mg/mL for HES derivatives prepared according to example 9.1(c) and9.1(d).

9.1 mg/mL for the HES derivative prepared according to example 9.1(e).

10.5 mg/mL for the HES derivative prepared according to example 9.1(f).

17.25 mg/mL for the HES derivative prepared according to example 9.1(g).

9 mg/mL HES50/0.7 (Supramol Parenteral Colloids GmbH, Rosbach-Rodheim,D) as reaction control. The molecular weight of the HES50/0.7 whenmeasured with LALLS-GPC was 47000 D and the DS was 0.76.

The respective reaction mixture was analysed by gel electrophoresis (seeFIG. 20).

Example 9.4 Synthesis of the ATIII-Conjugates by Reductive AminationExample 9.4(a) Buffer Exchange

ATIII (Atryn, GTC Biotherapeutics, Framingham, Mass., USA) was dissolvedwith 10 ml water to yield a solution of 25 mg/ml ATIII in 5 mM sodiumcitrate, 67 mM glycine and 68 mM sodium chloride, pH7.0. 1 ml of thissolution was diluted with cold 0.1 M sodium acetate buffer, pH 5.0,concentrated by diafiltration at 4° C. to 4 ml with a Vivaspin 20 mLconcentrator (VS2001, 10 KD MWCO, PES membrane, Vivascience AG,Hannover, D) and re-diluted to 20 ml with buffer. This diafiltration wasrepeated twice. The final concentration in the last diafiltration stepwas 3 mg/ml.

Example 9.4(b) Reaction of ATIII with Reaction Products of Example9.2(b) and 9.2(d)

To 1 mL of a solution of ATIII after buffer exchange into 0.1 M sodiumacetate buffer, pH 5.0 1 mL of a solution of the HES-derivative in 0.1 Msodium acetate buffer, pH 5.0 and 1 ml of a 60 mM solution of sodiumcyanoborohydride in the same buffer were added and the solution wasincubated for 15.5 h at 4° C. All the solutions were cooled to 0° C.before mixing.

The following final HES concentrations were employed:

13 mg/mL for the HES derivative prepared according to example 9.2(b).

64.7 mg/mL for the HES derivative prepared according to example 9.2(d).

64.7 mg/mL HES50/0.7 (Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) as reaction control.

The respective reaction mixture was analysed by gel electrophoresis.

Example 10 Synthesis of IFN-Alpha Conjugates via Activated Aldonic Acids

The IFN-alpha used was a recombinant human Interferon alpha-2bmanufactured by recombinant DNA technology using Escherichia coli (E.coli). It is composed of 165 amino acids and presents an amino acidsequence, which is identical to the natural human interferon alpha 2b(hIFN-alpha 2b).

Example 10.1 Synthesis of Oxidized HES (Oxo-HES)

Oxidized HES was prepared from HES (MW=57 kD, DS=0.76, SupramolParenteral Colloids GmbH, Rosbach-Rodheim, D) according to DE 196 28 705A1.

Example 10.2 Synthesis of NHS-Activated Oxo-HES

4.81 g ox-HES 50/0.7 as prepared in example 10.1 were dried in an ovenat 80° C. over night. The ox-HES is dissolved at 80° C. in dry DMF andcooled to room temperature.

From a solution of 102.1 mg N,N′-Disuccinimidylcarbonate (Aldrich) in 1ml dry DMF, 400 ml are dropped to the stirred reaction vessel andstirred for 2 hours at room temperature.

The reaction mixture is dropwise added to 50 ml dry acetone and theprecipitated product collected by centrifugation and washed with 4×50 mldry acetone, where the resuspended product is centrifuged. The residualsolvent is removed at room temperature in vacuo.

Example 10.3 Synthesis of an IFN-Alpha Conjugate via Activated AldonicAcid (AAA)

The protein was concentrated using Amicon Ultra filtration modules 4 (5kDa molecular weight cut-off (MWCO)) in a cooled centrifuge (4° C.) to afinal concentration of 10 mg/ml. The buffer was exchanged during thisprocedure to isotonic phosphate buffer, pH 8.

For coupling, 9 mg of the protein solution were incubated with the 20fold molar amount of the NHS activated ox-HES of example 10.1 for twohours at room temperature. The reaction mixture was purified from NHS byultrafiltration using Amicon Ultra filtration modules 4 (5 kDa MWCO) ina cooled centrifuge (4° C.). The buffer was exchanged during thisprocedure to 25 mM sodium phosphate, 30 mM sodium chloride, 0.3 mM EDTA,at pH 7.5.

The reaction yield of the experiment was >90% as determined by SEC (seeFIG. 22).

Example 10.4 Purification of IFN-Alpha-HES

The purification of the sample was performed at room temperature usingan ÄKTA explorer 10 equipment. The column containing 5 ml Q-SepharoseFast Flow was equilibrated with 5 CV of buffer A1 (20 mM Tris/HCl, pH8.0). The samples were diluted 1:16 with buffer A and were applied byusing the sample pump at a flow rate of 6 ml/min. Following washing ofthe sample pump with 20 ml of buffer A1, the column was further washedwith 15 ml of buffer A1 at a flow rate of 1.0 ml/min. Elution wasperformed by using a linear gradient from 0-100% of buffer B1 (0.3 MNaCl in 20 mM Tris/HCl, pH 8.0) over 37.5 min and an isocratic run withbuffer B over 12.5 min at a flow rate of 0.8 ml/min. The column wasregenerated by using 15 ml of buffer B2 (1.5 M NaCl in 20 mM Tris/HCl,pH 8.0) followed by 5 ml of buffer B at a flow rate of 0.8 ml/min.Reequilibration for the next run was performed by using 25 ml of bufferA1 and a flow rate of 1.0 ml/min.

Equipment: Äkta explorer 10 (Amersham Bioscience) with: Pump P-903 MixerM-925 with 0.6 ml chamber Monitor UV-900 with 10 mm flow cell MonitorpH/C-900 Pump P-950 (sample pump) Software Unicorn Version 3.21 Column:Amersham Bioscience C 10/10 Column material: Q-Sepharose Fast Flow, LotNo. OD 06453 Column volume: 5 ml Program: Q Seph 5 ml without Inject forIFN-α Eluent A1: 20 mM Tris/HCl, pH 8.0 (PL0935) Eluent B1: 0.3M NaCl in20 mM Tris/HCl, pH 8.0 (PL0938) Eluent B2: 1.5M NaCl in 20 mM Tris/HCl,pH 8.0 (PL0937)Method

Volume Step Eluent Flow rate 25 ml Equilibration 100% Eluent A1 1 ml/min40 ml Load sample Probe in Eluent A1 6 ml/min 20 ml Wash sample pump100% Eluent A1 6 ml/min 15 ml Wash column 100% Eluent A1 1 ml/min 30 mlElution (Gradient) 0 to 100% Eluent B1 0.8 ml/min 10 ml Elution(Isokratic) 100% Eluent B1 0.8 ml/min 15 ml Regeneration 100% Eluent B20.8 ml/min  5 ml Regeneration 100% Eluent B1 0.8 ml/min 25 mlReequilibration 100% Eluent Al 1.0 ml/min Detection 280 nm, 260 nm, 220nm pH Conductivity Fractionation 1 ml fractions

Example 11 Description of IFN Alpha Antiviral Activity Bioassay

After pre-diluting the Test Items in cell culture medium, serialtwo-fold dilutions were prepared. In 96 well microtiter plates, dilutedInterferon was added—in four-fold replicate per dilution—to freshlytrypsinized MDBK cells (40.000 cells per well). The assays wereincubated for 24 hours at 37° C. (total volume per well: 150 μL (example11.1) or 175 μl (example 11.2)).

Subsequently, 50 μL diluted VSV stock solution were added to each well(except for the positive control wells) resulting in a multiplicity ofinfection of 0.1.

The following controls were included in each assay: 12 wells thatreceived virus plus cell culture medium instead of Interferon (negativecontrol) and 12 wells that received cell culture medium instead ofInterferon and virus (positive control). The assays were incubated for42 hours at 37° C.

At the end of the incubation period, the cell culture supernatant ofeach well was replaced with 50 μL of a solution of MTT (at least 2 mg/mLin cell culture medium). The cells were incubated for three hours. Thepurple formazan dye formed by the proliferating cells was solubilized byadding 100 μL solution of isopropanol/HCl (isopropanol with 40 mM HCl)to each well. Subsequently, the absorbance values of the solutions weremeasured at 570/630 nm in a microtiter plate reader.

The proliferative activity of MDBK cells grown in the presence ofInterferon and VSV was calculated for each dilution of Interferon asfollows:

$\frac{\begin{pmatrix}{{{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{four}\mspace{14mu}{Interferon}\mspace{14mu}{treated}\mspace{14mu}{wells}} -} \\{{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{negative}\mspace{14mu}{control}}\end{pmatrix}*100}{\begin{matrix}{\left( {{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{positive}\mspace{14mu}{control}}\; \right) -} \\\left( {{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{negative}\mspace{14mu}{control}} \right)\end{matrix}}$

The antiviral activity of Interferon-alpha was determined in fourseparate assays for each of the Test Items.

Example 11.1 Antiviral Activity of Intron® A Relative to NIH Standard

In all experiments, Intron® A (IFN-alpha 2b, Schering-Plough),calibrated against NIH-standard rhIFN-alpha 2a (NIAID, NIH, Bethesda,USA, Gxa01-901-535) was used as an internal lab reference. TheNIH-standard had a specific activity of 9,000 IU/ml. The internal labreference Intron® A had a specific activity of 8,487,000 IU/ml in thetest as described in example 11 (see FIG. 23).

Example 11.2 Antiviral Activity of IFN-Alpha-HES Relative to Intron® A

In the assay system described in example 11, the conjugate from example10.4 was tested compared to Intron® A. The CPE50 concentration of bothmaterials was calculated. IFN-alpha-HES had more than 25% of theactivity of Intron® A (see FIG. 24).

Example 12 In vivo Bioactivity of IFN-Alpha-HES (PK Study in Mice)Example 12.1 Influence of Mouse Serum on Assay System as Described inExample 11

Dilutions of Interferon-alpha were prepared in cell culture medium(control) and in mouse serum (1:40 dilution and 1:80 dilution). Theassay was performed as described in example 11.

The antiviral activity of Interferon-alpha was determined in twoseparate assays for the control, for mouse serum 1:40 diluted as well asfor mouse serum 1:80 diluted. The results indicated that mouse serum at1:40 dilution and 1:80 does not affect the bioassay for antiviralactivity of Interferon-alpha.

Example 12.2 In vivo Study in Mice

Antiviral activity of pooled serum was tested in the antiviral assay.Serum was collected from two mice (female BALB/c mice, aged 8 weeks) ateach time, which were sacrificed 2 h, 4 h, 12 h, and 24 h posti.v.-injection of 30 μg/kg (based on the protein content) of IFN-alphaor the conjugate.

The serum samples were thawed and thoroughly homogenised by vortexing.Serial two-fold dilutions were prepared in cell culture medium. A vialof Intron® A was thawed and thoroughly homogenised by vortexing. Serialtwo-fold dilutions were prepared in cell culture medium.

The EC50-dilutions in the CPE-assay were determined from dose responsecurves of a 1:2 dilution series as described in example 11.

The half life of the materials was determined compared to unmodifiedstarting material and Pegasys. The half life was calculated from asemi-logarithmic plot of the EC50-dilution vs. time post injection (seeFIG. 25).

Antiviral activity was detected for IFN-alpha-HES up to 24 h. Ahalf-life increase by derivatisation of IFN-alpha with HES was observed(half life approx. 5 h). For unmodified IFN-alpha, the antiviralactivity of serum was too low to calculate a serum half-life.

Example 13 A1AT (α1AT, Alpha1aT) Conjugates Synthesized via ReductiveAmination Example 13.1 Synthesis of Amino-HES (A) from Oxidized HES

6.09 g of oxo-HES (MW=57,000 D, DS=0.76, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D, prepared according to DE 196 28 705 A1) wereheated over night at 80° C. in vacuo, dissolved under nitrogen in 32 mldry dimethyl sulphoxide (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen,D,) and 1.22 ml of 1,4-diaminobutane (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D) were added. After stirring at 40° C. for 17 h thereaction mixture was added to 150 ml of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., washed with 40 ml of an ice-cold 1:1 mixture ofacetone and ethanol (v/v) and collected by centrifugation. The crudeproduct was dissolved in 80 ml water, dialysed for 4 d against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The yield of isolated product was 82%.

Example 13.2 Synthesis of Aldehydo-HES (A) from Amino-HES (A) of Example13.1

125 mg 4-formylbenzoic acid and 174 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 38ml N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL), and 155 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 3.8 g of amino-HES (A) (prepared as described inexample 13.1) were added. After shaking for 19 h at 22° C., the reactionmixture was added to 160 ml of an ice-cold 1:1 mixture of acetone andethanol (v/v). The precipitated product was collected by centrifugationat 4° C., re-dissolved in 20 ml N,N-dimethylformamide and precipitatedwith 80 ml of an ice-cold 1:1 mixture of acetone and ethanol (v/v) asdescribed in example 13.1. After centrifugation, the precipitate wasdissolved in 50 ml water, dialysed for 2 d against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized. The yield of isolated product was 77%.

Example 13.3 Synthesis of Amino-HES (B) from Oxidized HES

10 g of oxo-HES (MW=57 kD, DS=0.76, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D, prepared according to DE 196 28 705 A1) were heatedover night at 80° C. in vacuo, dissolved under nitrogen in 52 ml drydimethyl sulphoxide (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D)and 2 ml of 1,4-diaminobutane (Fluka, Sigma-Aldrich Chemie GmbH,Taufkirchen, D) were added. After stirring at 40° C. for 17 h thereaction mixture was added to 350 ml of ice-cold 2-propanol (Carl RothGmbH+Co. KG, Karlsruhe, D). The precipitated product was collected bycentrifugation at 4° C., washed with 80 ml of ice-cold 2-propanol andcollected by centrifugation. The crude product was dissolved in 80 mlwater, dialysed for 2 d against water (SnakeSkin dialysis tubing, 3.5 kDcut off, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theyield of isolated product was 85%.

Example 13.4 Synthesis of Aldehydo-HES (B) from Amino-HES (B) of Example13.3

153 mg 4-formylbenzoic acid and 241 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 51ml N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 170 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 5.1 g of amino-HES (B) (prepared as described inexample 13.3) were added. After shaking for 16 h at 22° C., the reactionmixture was added to 360 ml of an ice-cold 1:1 mixture of acetone andethanol (v/v). The precipitated product was collected by centrifugationat 4° C., re-dissolved in 50 ml water and precipitated with 360 ml of anice-cold 1:1 mixture of acetone and ethanol (v/v) as described inexample 13.1. After centrifugation, the precipitate was dissolved in 50ml water, dialysed for 2 d against water (SnakeSkin dialysis tubing, 3.5kD cut off, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized.The yield of isolated product was 87%.

Example 13.5 Conjugation of Aldehydo-HES (A) and (B) to A1AT byReductive Amination

A mixture of 189 mg aldehydo-HES (B) (prepared as described in example13.4) and 172 mg aldehydo-HES (A) (prepared as described in example13.2) were dissolved in 2.88 ml reaction buffer (0.1 M sodium phosphatebuffer, 150 mM sodium chloride, pH 7.2). At 20° C., 1.67 ml of a 60 mMsodium cyanoborohydride solution in the same buffer were added followedby 0.455 ml of an A1AT solution (c (A1AT)=11.0 mg/ml in 0.1 M sodiumphosphate buffer, 150 mM sodium chloride, pH 7.2, A1AT=rh A1AT providedby GTC Biotherapeutics Inc., Framingham, Mass., lot No. 080604A). Themixture was incubated at 20° C. After 17 h, additional 6.7 mg sodiumcyanoborohydride dissolved in 200 μl of the reaction buffer were addedand the mixture was incubated for additional 24 h at the sametemperature. 10 μL of this solution were analysed after a totalincubation time of 25 h by gel electrophoresis (see FIG. 26)

Example 13.6 Conjugation of HES to A1AT by Reductive Amination (ReactionControl)

362 mg HES (MW=42 kD, DS=0.41, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were dissolved in 2.88 ml reaction buffer (0.1 Msodium phosphate buffer, 150 mM sodium chloride, pH 7.2). At 20° C.,1.67 ml of a 60 mM sodium cyanoborohydride solution in the same bufferwere added followed by 0.455 ml of a A1AT solution (c (A1AT)=11.0 mg/mlin 0.1 M sodium phosphate buffer, 150 mM sodium chloride, pH 7.2,α1AT=rh α1AT provided by GTC Biotherapeutics Inc., Framingham, Mass.,lot No. 080604A). The mixture was incubated at 20° C. After 17 h,additional 6.7 mg sodium cyanoborohydride dissolved in 200 μl of thereaction buffer were added and the mixture was incubated for additional24 h at the same temperature. 10 μL of this solution were analysed aftera total incubation time of 25 h by gel electrophoresis (see FIG. 27).

Example 13.7 Purification of HES-A1AT Conjugate by Ion ExchangeChromatography (IEC)

Conjugates of A1AT were purified by Ion Exchange Chromatography on aHiTrap Q HP column using an ÄKTA-Explorer chromatography system (bothfrom

Amersham Biosciences). The purification was performed in accordance withthe isolation of A1AT from human plasma as described in “Chen, Hammond,Lang and Lebing, Purification of α₁ Proteinase Inhibitor from HumanPlasma Fraction IV-1 by Ion Exchange Chromatography, VoxSanguinis 1998,74, 232-241”.

Sample preparation: buffer exchange on a HiPrep 26/10 Desalting column(Amersham Biosciences) in combination with the ÄKTA-Explorerchromatography system using 20 mM sodium phosphate, 20 mM sodiumchloride, pH 8 as eluent.

Buffer exchange was performed after dilution of the crude reactionmixture (preparation as described in example 13.5, approximately 5 ml)with desalted water to a final volume of 10 ml using the followingparameters:

Column: HiPrep 26/10 Desalting Flow rate: 10 ml/min Eluent: 20 mM sodiumphosphate, 20 mM sodium chloride, pH 8 Sample volume: 10 ml Eluatefractionation: 2.5 ml Equilibration: 5 column volumes Length of elution:2 column volumes

The first 14 ml of eluent were pooled, and binding buffer was added toyield a final volume of 20 ml. This solution, containing approximately 5mg protein, was purified by IEC using the following parameters:

Column: HiTrap Q HP 1 ml Flow rate: 1 ml/min Binding Buffer (BB): 20 mMsodium phosphate, 20 mM sodium chloride, pH 8 Elution Buffer (EB): 20 mMsodium phosphate, 1 M sodium chloride, pH 8 Sample volume: 20 ml Flowtrough fractionation: 2 ml Eluate fractionation: 1 ml Startconcentration EB: 0% Equilibration: 5 column volumes Wash out unboundsample: 15 ml Target concentration EB: 15% Length of gradient: 20 ml

The fractions collected after chromatography were analysed by SDS-Page.Fractions containing HES-A1AT conjugate were pooled (elution volume from40 to 47 ml corresponding to fractions B1-C6, see FIG. 27). In some ofthe pooled fractions a small amount of unreacted A1AT was detectable.The initial concentration of the pooled fraction after chromatographydetermined by BCA (Pierce Cat. No. 23225), using A1AT (provided by GTCBiotherapeutics Inc., Framingham, Mass., lot No. 080604A) as referencestandard) was 170 μg/ml. After dilution and buffer exchange into 20 mMsodium phosphate, 150 mM sodium chloride, pH 7.2 the resulting proteinconcentration was 54.5 μg/ml (BCA (pierce with A1AT from GTC asreference standard)). This final solution was used to determinate theinhibitory efficiency of the conjugate.

Example 13.8 Determination of the in vitro Inhibition Capacity ofHES-A1AT Conjugate for Human Granulocyte Elastase

Elastase Inhibitory activity tests of the conjugates were performedaccording to Castillo et al., Anal. Biochem. 1979, 99, 53-64 using aTecan UV-VIS-Platereader Model Sunrise.

This assay is based on the release of p-nitroaniline fromN-Met-O-succinyl-Ala-Ala-Pro-Val-p-NO₂-anilin catalyzed by elastase.This hydrolysis can be followed by the increase of absorbance at 405 nm.The initial hydrolysis rate is in close correlation to the activity ofthe enzyme. The assay was carried out in absence and in the presence ofdifferent concentrations of the inhibitor to be tested. The decrease ofenzyme activity according to the inhibitory activity of the substancestested is represented in a decrease of the slope in the A₄₀₅ versus timeplot. The residual elastase activity in presence of a certain inhibitorconcentration is given by the slope of the inhibited curve divided bythe slope of the uninhibited curve. There is a linear correlationbetween the residual enzyme activity and the inhibitor concentration. Byusing linear regression, a linear smooth line can be achieved and theresidual enzyme activity for a given inhibitor concentration can becalculated. By this way the inhibitory activity (=1-residual enzymeactivitiy) of the same concentration of different inhibitors can becompared. (see FIG. 28)

The following parameters were used:

Substrate concentration: 1.5 mM Elastase activity: 7.5 mU Wavelength:405 nm Temperature: 20° C. Time interval: 15 s Kinetic cycles: 25Measure Mode: Center

The assay solution consisted of 300 μl buffer (0.1 M Hepes, 0.5 M NaCl,0.05% (m/v) Triton X-100, pH 7.5) containing 10% DMSO, 1.5 mMN-Met-O-succinyl-Ala-Ala-Pro-Val-p-NO₂-anilin, 7.5 mU Elastase andvarying amounts of inhibitors.

Elastase was purchased from Serva Electrophoresis GmbH, Heidelberg. Allother substances were purchased from Sigma Aldrich, Taufkirchen.

The inhibitory activity of the conjugate synthesized as described inexample 13.5 was tested in comparison with Prolastin® HS (Bayer VitalGmbH, Leverkusen, Germany Lot No. PR4HA43) as reference and with A1AT(GTC Biotherapeutics Inc., Framingham, Mass., lot No. 080604A) asstarting material for the conjugation. The residual enzyme activity vs.concentration plot is given in FIG. 28. Linearity for all curves wasR²>0.98. In the below, IC₅₀-values and elastase inhibition for c(inhibitor)=1 μg/ml are given, as well as the inhibitory activity ofstarting material and conjugate in relation to the reference. Dataoutlined in the table below clearly demonstrate that the major part ofthe A1AT activity remained after conjugation with HES.

Table of Example 13.8

elastase inhibition activity inhibition in relation linear smooth lineIC₅₀ c (inhibitor) = to Prolastin inhibitor equitation [μg/ml] 1 μg/ml[%] [%] Prolastin Y = −0.6754x + 0.9627 0.685 71.3 α1AT Y = −0.5046x +0.9558 0.903 54.9 77.0 HES-A1AT-conjugate Y = −0.3757x + 0.9627 1.23241.3 57.9

Example 13.9 Determination of the in-vivo Half-Live of HES-rh alpha1ATConjugate in Comparison to rh alpha1AT and Plasma Derived h alpha1AT

Female mice aged 8-10 weeks (BALB/cOlaHsd, Harlan GmbH, Borchen,Germany) were utilized as test organism (42 mice, 14 per sample). The“is bodyweight” of each animal was detected right before administrationof the different sample solutions. 100 μl of a 50 μg/ml solution of thesamples outlined below in a puffer pH=7.2 (20 mmol sodium phosphate, 150mmol sodium chloride) were injected intravenously in the tail vein ofthe mice.

Sample 1: rh alpha1AT (GTC Biotherapeutics Inc., Framingham, MA, lot No.080604A) Sample 2: rh alpha1AT-HES conjugate as prepared in example 13.5Sample 3: plasma derived h alpha1AT (SERVA Electrophoresis GmbH,Heidelberg, Germany)

At 1, 2, 4, 10, 24, 31.5 and 48, hours after injection, two mice of eachgroup were killed and whole blood samples (˜500 μl) were withdrawn fromthe heart of the animals. Serum was prepared using Microvette® 500 Z-Gel(Sarstedt, Nümbrecht, Germany). The serum samples were stored at −80° C.until the beginning of the alpha1AT concentration measurements.

alpha1AT concentrations were detected using a commercially availablealpha1AT-ELISA (Immundiagnostik, Bensheim, Germany) following themanufacturers instructions.

The results obtained demonstrate a significant plasma half-life increasefor the rh alphalAT-HES conjugate in comparison to the not modified rhalpha1AT starting material. The measured half-life of the conjugate isin the same range than the one of the plasma derived h alpha1ATaccording to the following table.

Table of Example 13.9 Plasma Half-Life of Samples 1-3

Sample No Plasma half-life in mice [h] 1 1.2 2 3.6 3 3.2

Example 14 Synthesis of HES-IFN-Alpha Conjugates via Reducitve Amination

The IFN-α used was a recombinant human Interferon alpha-2b manufacturedby recombinant DNA technology using Escherichia coli (E. coli). It iscomposed of 165 amino acids and presents an amino acid sequence which isidentical to the natural human interferon alpha 2b (hIFN-alpha 2b).

Example 14.1 Synthesis of Oxo-HES

HES oxidised at its reducing end as described hereinunder (oxo-HES) wasprepared from HES using an alkaline iodine solution as described in DE196 28 705 A1 the respective contents of which (example A, column 9,lines 6 to 24) is incorporated herein by reference.

Example 14.2 Synthesis of HES Derivatives

In a two step procedure, oxo-HES of example 14.1 was modified at itsreducing end with an amine, and an aldehydo group was introduced in asecond reaction. The resulting aldhydo-HES was used to produce theIFN-alpha-HES conjugates via reductive amination as described in example14.3.

Example 14.2.1 Synthesis of Amino-HES from Oxo-HES of Example 14.1

5.12 g of oxo-HES of example 14.1 (MW=14.5 kD, DS=0.41, SupramolParenteral Colloids GmbH, Rosbach-Rodheim, D) were heated over night at80° C. in vacuo and dissolved under nitrogen in 25 mL dry dimethylsulphoxide (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 5.13mL of 1,4-diaminobutane were added. After stirring at 40° C. for 17 hthe reaction mixture was added to 150 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., washed with 40 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v) and collected by centrifugation. The crudeproduct was dissolved in 80 mL water, dialysed for 4 d against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The yield of isolated product was 67%.

Example 14.2.2 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.1

105 mg 4-formylbenzoic acid and 135 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 7mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 135 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 0.7 g of amino-HES (synthesised as described inexample 14.2.1) were added. After shaking for 18 h at 22° C., thereaction mixture was added to 42 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., re-dissolved in 5 mL DMF and precipitated with42 mL ethanol/acetone as described above. After centrifugation, thecollected precipitate was dissolved with water, dialysed for 4 d againstwater (SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio SciencesDeutschland GmbH, Bonn, D) and lyophilized. The yield of isolatedproduct was 95%.

Example 14.2.3 Synthesis of Amino-HES from Oxo-HES of Example 14.1

6.02 g of oxo-HES of example 14.1 (MW=14.7 kD, DS=0.76, SupramolParenteral Colloids GmbH, Rosbach-Rodheim, D) were heated over night at80° C. in vacuo and dissolved under nitrogen in 32 mL dry dimethylsulphoxide (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 6.03mL of 1,4-diaminobutane were added. After stirring at 40° C. for 17 hthe reaction mixture was added to 150 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., washed with 40 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v) and collected by centrifugation. The crudeproduct was dissolved in 80 mL water, dialysed for 4 d against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The yield of isolated product was 52%.

Example 14.2.4 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.3

150 mg 4-formylbenzoic acid and 230 mg 1-hydroxy-1H-benzotriazole (both

Aldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 10mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 204 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 1 g of amino-HES (synthesised as described inexample 14.2.3) were added. After shaking for 19 h at 22° C., thereaction mixture was added to 84 mL of ice-cold 2-propanol. Theprecipitated product was collected by centrifugation at 4° C.,re-dissolved in 50 mL water, dialysed for 2 d against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized. The yield of isolated product was 83%.

Example 14.2.5 Synthesis of Amino-HES from oxo-HES of Example 14.1

5 g of oxo-HES of example 14.1 (MW=28 kD, DS=0.41, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D) were heated over night at 80° C. invacuo and were then dissolved under nitrogen in 28 mL dry dimethylsulphoxide (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 1.67mL of 1,4-diaminobutane were added. After stirring at 40° C. for 17 hthe reaction mixture was added to 175 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C. The crude product was dissolved in 40 mL water,dialysed for 2 d against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theyield of isolated product was not determined.

Example 14.2.6 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.5

130 mg 4-formylbenzoic acid and 153 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 36mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 110 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 2.61 g of amino-HES (synthesised as described inexample 14.2.5) were added. After shaking for 22.5 h at 22° C., thereaction mixture was added to 160 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C. and washed with an ice-cold 1:1 mixture ofacetone and ethanol (v/v). After centrifugation, the precipitate wasdissolved in 30 mL water, dialysed for 1 d against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized. The yield of isolated product was 81%.

Example 14.2.7 Synthesis of Amino-HES from Oxo-HES of Example 14.1

5 g of oxo-HES of example 14.1 (MW=30.8 kD, DS=0.76, Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D) were heated over night at 80° C. invacuo and were then dissolved under nitrogen in 28 mL dry dimethylsulphoxide (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 1.67mL of 1,4-diaminobutane were added. After stirring at 40° C. for 17 hthe reaction mixture was added to 175 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C. The crude product was dissolved in 40 mL water,dialysed for 2 d against water (SnakeSkin dialysis tubing, 3.5 kD cutoff, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theyield of isolated product was not determined.

Example 14.2.8 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.7

122 mg 4-formylbenzoic acid and 144 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 34mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 103 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 2.46 g of amino-HES (synthesised as described inexample 14.2.7) were added. After shaking for 22.5 h at 22° C., thereaction mixture was added to 160 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C. and washed with an ice-cold 1:1 mixture ofacetone and ethanol (v/v). After centrifugation, the precipitate wasdissolved in 30 mL water, dialysed for 4 d against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized. The yield of isolated product was 87%.

Example 14.2.9 Synthesis of Amino-HES from Oxo-HES of Example 14.1

10 g of oxo-HES (MW=42.1 kD, DS=0.41, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were heated for two days at 80° C. in vacuo and werethen dissolved under nitrogen in 53 mL dry dimethyl sulphoxide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 2.01 mL of1,4-diaminobutane were added. After stirring at 40° C. for 17 h thereaction mixture was added to 350 mL of ice-cold 2-propanol (Carl RothGmbH+Co. KG, Karlsruhe, D). The precipitated product was collected bycentrifugation at 4° C., washed with 80 mL of ice-cold 2-propanol andcollected by centrifugation. The crude product was dissolved in 80 mLwater, dialysed for 2 d against water (SnakeSkin dialysis tubing, 3.5 kDcut off, Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. Theyield of isolated product was 76%.

Example 14.2.10 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.9

900 mg 4-formylbenzoic acid and 1053 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 30mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 930 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 3 g of amino-HES (synthesised as described inexample 14.2.9 and dissolved in 20 mL N,N-dimethylformamide) were added.After shaking for 22.5 h at 22° C., the reaction mixture was added to210 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v). Theprecipitated product was collected by centrifugation at 4° C. and washedwith an ice-cold 1:1 mixture of acetone and ethanol (v/v). Aftercentrifugation, the precipitate was dissolved in 30 mL water, dialysedfor 2 d against water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized. The yield ofisolated product was 97%.

Example 14.2.11 Synthesis of Amino-HES from Oxo-HES of Example 14.1 (A)

6.09 g of oxo-HES (MW=56.8 kD, DS=0.76, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were heated over night at 80° C. in vacuo andwere then dissolved under nitrogen in 32 mL dry dimethyl sulphoxide(Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 1.22 mL of1,4-diaminobutane were added. After stirring at 40° C. for 17 h thereaction mixture was added to 150 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., washed with 40 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v) and collected by centrifugation. The crudeproduct was dissolved in 80 mL water, dialysed for 4 d against water(SnakeSkin dialysis tubing, 3.5 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The yield of isolated product was 82%.

Example 14.2.12 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.11

125 mg 4-formylbenzoic acid and 174 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 38mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 155 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 3.8 g of amino-HES (synthesised as described inexample 14.2.11) were added. After shaking for 19 h at 22° C., thereaction mixture was added to 160 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., re-dissolved in 20 mL N,N-dimethylformamide andprecipitated with 80 mL of an ice-cold 1:1 mixture of acetone andethanol (v/v) as described above. After centrifugation, the precipitatewas dissolved in 50 mL water, dialysed for 2 d against water (SnakeSkindialysis tubing, 3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn,D) and lyophilized. The yield of isolated product was 77%.

Example 14.2.13 Synthesis of Amino-HES from Oxo-HES of Example 14.1 (B)

10 g of oxo-HES (MW=56.8 kD, DS=0.76, Supramol Parenteral Colloids GmbH,Rosbach-Rodheim, D) were heated over night at 80° C. in vacuo and werethen dissolved under nitrogen in 53 mL dry dimethyl sulphoxide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 2 mL of 1,4-diaminobutanewere added. After stirring at 40° C. for 17 h the reaction mixture wasadded to 350 mL of ice-cold 2-propanol (Carl Roth GmbH+Co. KG,Karlsruhe, D). The precipitated product was collected by centrifugationat 4° C., washed with 80 mL of ice-cold 2-propanol and collected bycentrifugation. The crude product was dissolved in 80 mL water, dialysedfor 2 d against water (SnakeSkin dialysis tubing, 3.5 kD cut off, PerbioSciences Deutschland GmbH, Bonn, D) and lyophilized. The yield ofisolated product was 85%.

Example 14.2.14 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.13

153 mg 4-formylbenzoic acid and 241 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 51mL N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 170 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, 5.1 g of amino-HES (synthesised as described inexample 14.2.13) were added. After shaking for 16 h at 22° C., thereaction mixture was added to 360 mL of an ice-cold 1:1 mixture ofacetone and ethanol (v/v). The precipitated product was collected bycentrifugation at 4° C., re-dissolved in 50 mL water and precipitatedwith 360 mL of an ice-cold 1:1 mixture of acetone and ethanol (v/v) asdescribed above. After centrifugation, the precipitate was dissolved in50 mL water, dialysed for 2 d against water (SnakeSkin dialysis tubing,3.5 kD cut off, Perbio Sciences Deutschland GmbH, Bonn, D) andlyophilized. The yield of isolated product was 87%.

Example 14.2.15 Synthesis of Amino-HES from Oxo-HES of Example 14.1

5.0 g of oxo-HES (MW=29.3 kD, DS=0.86, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were heated over night at 80° C. in vacuo,dissolved under nitrogen in 20 ml dry dimethyl sulphoxide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 1.67 ml of1,4-diaminobutane (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D)were added. After stirring at 40° C. for 30.5 h the reaction mixture wasadded to 175 ml of ice-cold 1:1 (v/v) mixture of acetone (Carl RothGmbH+Co. KG, Karlsruhe, D) and ethanol (Sonnenberg, DAB, Braunschweig,D). The precipitated product was collected by centrifugation for 120 minat 4° C., dissolved in 40 ml water, dialysed for 2 d against water(SnakeSkin dialysis tubing, 10 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The yield of isolated product was 87%.

Example 14.2.16 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.15

150 mg 4-formylbenzoic acid and 230 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 10ml N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 166 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, a solution of 3.02 g AminoHES (synthesized asdescribed in example 14.2.15) in 20 ml DMF were added. After shaking for16 h at 22° C., the reaction mixture was added to 215 ml of an ice-cold1:1 mixture (v/v) of acetone (Carl Roth GmbH+Co. KG, Karlsruhe, D) andethanol (Sonnenberg, DAB, Braunschweig, D). The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 20 ml water andprecipitated with acetone/ethanol as described above. Aftercentrifugation, the precipitate was dissolved in 30 ml water, dialysedfor 2.5 d against water (SnakeSkin dialysis tubing, 10 kD cut off,Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. The yield ofisolated product was 87%.

Example 14.2.17 Synthesis of Amino-HES from Oxo-HES of Example 14.1

5.0 g of oxo-HES (MW=97.9 kD, DS=0.76, Supramol Parenteral ColloidsGmbH, Rosbach-Rodheim, D) were heated over night at 80° C. in vacuo,dissolved under nitrogen in 20 ml dry dimethyl sulphoxide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) and 0.50 ml of1,4-diaminobutane (Fluka, Sigma-Aldrich Chemie GmbH, Taufkirchen, D)were added. After stirring at 40° C. for 30.5 h the reaction mixture wasadded to 175 ml of ice-cold 1:1 (v/v) mixture of acetone (Carl RothGmbH+Co. KG, Karlsruhe, D) and ethanol (Sonnenberg, DAB, Braunschweig,D). The precipitated product was collected by centrifugation for 120 minat 4° C., dissolved in 40 ml water, dialysed for 2 d against water(SnakeSkin dialysis tubing, 10 kD cut off, Perbio Sciences DeutschlandGmbH, Bonn, D) and lyophilized. The yield of isolated product was 90%.

Example 14.2.18 Synthesis of Aldehydo-HES from Amino-HES of Example14.2.17

73 mg 4-formylbenzoic acid and 112 mg 1-hydroxy-1H-benzotriazole (bothAldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in 10ml N,N-dimethylformamide (Peptide synthesis grade, Biosolve,Valkenswaard, NL) and 81.3 μL N,N′-diisopropylcarbodiimide (Fluka,Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were added. After incubationat 21° C. for 30 min, a solution of 3.09 g AminoHES (prepared asdecribed in example 14.2.17) in 20 ml DMF were added. After shaking for16 h at 22° C., the reaction mixture was added to 215 ml of an ice-cold1:1 mixture (v/v) of acetone (Carl Roth GmbH+Co. KG, Karlsruhe, D) andethanol (Sonnenberg, DAB, Braunschweig, D). The precipitated product wascollected by centrifugation at 4° C., re-dissolved in 20 ml water andprecipitated with acetone/ethanol as described above. Aftercentrifugation, the precipitate was dissolved in 30 ml water, dialysedfor 2.5 d against water (SnakeSkin dialysis tubing, 10 kD cut off,Perbio Sciences Deutschland GmbH, Bonn, D) and lyophilized. The yield ofisolated product was 96%.

Example 14.3 Synthesis IFN-Alpha Conjugates via Reductive AminationExample 14.3.1 Conjugation to IFN-Alpha at a 20 μg Scale

To 0.675 mg IFN-alpha, dissolved in 0.375 ml of 25 mM sodium phosphatebuffer pH 7.5, containing 150 mM NaCl and 0.3 mM EDTA, were added 4 mlof the reaction buffer (0.1 M sodium acetate buffer pH 5.0) and thesolution was centrifuged for 30 min at 3939×g in a Vivaspin 6concentrator (Viva Science, 5 kD MWCO, Hannover, Germany). The washingprocedure was repeated twice by dilution of the residual solution withthe reaction buffer to 6 ml and centrifugation as described. The volumeof the final IFN-alpha solution was 0.236 ml, corresponding to acalculated final concentration of 2.86 mg/ml IFN-alpha. The proteinconcentration was not checked experimentally.

To 7 μl of the IFN-alpha solution prepared as described above and cooledto 0° C., 10 μl (50 equiv.) of the respective aldehydo-HES (see tablebelow) solution and 11.3 μL of a 60 mM sodium cyanoborohydride solution,both in the same buffer (sodium acetate, pH 5.0) and cooled to 0° C.,were added and the mixture was incubated for 17 h at 0° C. The reactionmixture was analysed by gel electrophoresis. The followingconcentrations of the aldehydo-HES solutions were employed:

Table of example 14.3.1

Concentration Entry HES-Derivative [mg/ml] A aldehydo-HES (example14.2.2) 52 B aldehydo-HES (example 14.2.4) 52 C aldehydo-HES (example14.2.6) 156 D aldehydo-HES (example 14.2.8) 156 E aldehydo-HES (example14.2.10) 260 F aldehydo-HES (A) (example 14.2.12) 260 G Without HESderivative but with NaCNBH₃ — I Without HES derivative and withoutNaCNBH₃ — J non-oxidized HES (Mw 7.6 kD, DS = 0.41) 52 with NaCNBH₃ Knon-oxidized HES (Mw 7.6 kD, DS = 0.41), 52 without NaCNBH₃SDS-Page analysis of the conjugates is shown in FIG. 29.

Example 14.3.2 Conjugation to IFN-Alpha at a 3 mg Scale

To 20 mg IFN-alpha, dissolved in 25 mM sodium phosphate buffer pH 7.5,containing 150 mM NaCl and 0.3 mM EDTA, were added 8 ml of the reactionbuffer (0.1 M sodium acetate buffer pH 5.0) and the solution wascentrifuged for 99 min at 3939×g in a Vivaspin 15R concentrator (VivaScience, 5 kD MWCO, Hannover, Germany). The washing procedure wasrepeated twice by dilution of the residual solution with the reactionbuffer to 18 ml and centrifugation as described. The final IFN-alphasolution was diluted with reaction buffer to 6.66 ml giving a finalcalculated concentration of 3 mg/ml IFN-alpha. The protein concentrationwas not checked experimentally.

To 1 ml of the IFN-alpha solution prepared as described above and cooledto 0° C., 1 ml of the aldehydoHES solution (75 equiv.) and 1 ml of a 60mM sodium cyanoborohydride solution, both in the same buffer (sodiumacetate, pH 5.0) and cooled to 0° C., were added and the mixture wasincubated for 22 h at 0° C. The reaction mixture was purified afteranalysis by gel electrophoresis. For the reaction described in entry G,only 0.666 μl of the corresponding solutions were used. The followingconcentrations of the aldehydoHES solutions were employed:

Table of example 14.3.2

Concentration Entry HES-Derivative [mg/ml] A aldehydo-HES (example14.2.2) 117 B aldehydo-HES (example 14.2.4) 117 C aldehydo-HES (example14.2.6) 350 D aldehydo-HES (example 14.2.8) 350 E aldehydo-HES (example14.2.10) 584 F aldehydo-HES (A) (example 14.2.12) 584 G non-oxidized HES(Mw 7.6 kD, DS = 0.41) 117SDS-Page analysis of the conjugates is shown in FIG. 30.

Example 14.3.3 Conjugation to IFN-Alpha at a 3 mg Scale

14.3.3.1 Conjugation of AldehydoHES as Prepared in Example 14.2.16 toIFNα by Reductive Amination

To 10 mg IFNα, dissolved in 25 mM sodium phosphate buffer pH 7.5,containing 150 mM NaCl and 0.3 mM EDTA, were added 8 ml of the reactionbuffer (0.1 M sodium acetate buffer pH 5.0) and the solution wascentrifuged for 30 min at 3939×g in a Vivaspin 15R concentrator (VivaScience, 5 kD MWCO, Hannover, Germany). The washing procedure wasrepeated twice by dilution of the residual solution with the reactionbuffer to 18 ml and centrifugation as described. The final IFNα solutionwas diluted with reaction buffer to 3.33 ml giving a final calculatedconcentration of 3 mg/ml IFNα. The protein concentration was not checkedexperimentally.

To 1 ml of the IFNα solution prepared as described above and cooled to0° C., 1 ml of the aldehydoHES solution as prepared in example 14.2.16(75 equiv., 352 mg/ml) and 1 ml of a 60 mM sodium cyanoborohydridesolution, both in the same buffer and cooled to 0° C., were added andthe mixture was incubated for 22 h at 0° C. The reaction mixture waspurified after analysis by gel electrophoresis. For gel electrophoresisan XCell Sure Lock Mini Cell (Invitrogen GmbH, Karlsruhe, D) and aConsort E143 power supply (CONSORTnv, Turnhout, B) were employed. A 12%Bis-Tris gel together with a MOPS SDS running buffer at reducingconditions (both Invitrogen GmbH, Karlsruhe, D) were used according tothe manufactures instruction.

14.3.3.2 Conjugation of AldehydoHES as Prepared in Example 14.3.18 toIFNα by Reductive Amination

To 1 ml of the IFNα solution prepared as described in 14.3.3.1 andcooled to 0° C., 2 ml of the aldehydoHES solution as prepared in example14.3.18 (75 equiv., 369 mg/ml) and 1.5 ml of a 60 mM sodiumcyanoborohydride solution, both in the same buffer and cooled to 0° C.,were added and the mixture was incubated for 22 h at 0° C. The reactionmixture was purified after analysis by gel electrophoresis. For gelelectrophoresis a XCell Sure Lock Mini Cell (Invitrogen GmbH, Karlsruhe,D) and a Consort E143 power supply (CONSORTnv, Turnhout, B) wereemployed. A 12% Bis-Tris gel together with a MOPS SDS running buffer atreducing conditions (both Invitrogen GmbH, Karlsruhe, D) were usedaccording to the manufactures instruction.

14.3.3.3 Reaction Control: Conjugation of HES10/0.4 (Mw 7.6 kD DS=0.41)to IFNα by Reductive Amination

To 1 ml of the IFNα solution prepared as described in 14.3.3.1 andcooled to 0° C., 1 ml of the HES10/0.4 solution (75 equiv., 117 mg/ml)and 1 ml of a 60 mM sodium cyanoborohydride solution, both in the samebuffer and cooled to 0° C., were added and the mixture was incubated for22 h at 0° C. The reaction mixture was purified after analysis by gelelectrophoresis. For gel electrophoresis an XCell Sure Lock Mini Cell(Invitrogen GmbH, Karlsruhe, D) and a Consort E143 power supply(CONSORTnv, Turnhout, B) were employed. A 12% Bis-Tris gel together witha MOPS SDS running buffer at reducing conditions (both Invitrogen GmbH,Karlsruhe, D) were used according to the manufactures instruction.

SDS-Page analysis of the conjugates is shown in FIG. 31.

Example 14.3.4 Conjugation to IFN-Alpha at a 16 mg Scale

The buffer of 20 mg IFN-alpha solution was exchanged as described inexample 14.3.2. The final IFN-alpha solution was diluted with reactionbuffer to 6.37 ml giving a final calculated concentration of 3.14 mg/mlIFN-alpha. 100 μl of this solution were diluted with 900 μl reactionbuffer and the protein concentration was determinedspectrophotometrically at 279 nm to 3.01 mg/ml, based on the molarextinction coefficient of 18000. After combination with the materialused for protein concentration determination the final volume was 7.0 mlwith a protein concentration of 2.74 mg/ml.

To 5.91 ml of this IFN-alpha solution (16.2 mg) prepared as describedabove and cooled to 0° C., a solution of 3.152 g of aldehydo-HES ofexample 14.2.14 (75 equiv.) in 5 ml reaction buffer and 6 ml of a 60 mMsodium cyanoborohydride solution, both in the same buffer (sodiumacetate, pH 5.0) and cooled to 0° C., were added and the mixture wasincubated for 22 h at 0° C. (see FIG. 32, Line A).

As a reaction control, 1.09 ml of the pre-cooled IFN-alpha solution (3mg) were mixed with 1 ml of a solution of 122 mg non-oxidzed HES (Mw 7.6kD, DS=0.41) in the reaction buffer and 1 ml of a 60 mM sodiumcyanoborohydride solution, both in the same buffer and cooled to 0° C.(see FIG. 32, line B).

SDS-Page analysis of the conjugate is shown in FIG. 32.

Example 14.4 Purification of the IFN-Alpha-HES Conjugates 14.4.1Purification of HES-IFN-α from Incubations of the Reductively AminatedProtein with Activated HES Derivatives (Separation of the Modified andUnmodified Protein from HES-Derivatives)

The purification of all samples was performed at room temperature usingan ÄKTA explorer 10 equipment. The column containing 3 ml Q-SepharoseFast Flow was equilibrated with 10 CV of buffer A (20 mM Tris/HCl, pH8.0). The samples were diluted 1:10 with buffer A and were applied byusing the sample pump at a flow rate of 1 ml/min. Following washing ofthe sample pump with 10 ml of buffer A, the column was further washedwith 6 CV of buffer A at a flow rate of 1.0 ml/min. Elution wasperformed by using a linear gradient from 0-100% of buffer B (0.3 M NaClin 20 mM Tris/HCl, pH 8.0) over 2 CV and an isocratic run with 0.5 CV ofbuffer B at a flow rate of 0.8 ml/min. The column was regenerated byusing 2 CV of buffer C (1.5 M NaCl in 20 mM Tris/HCl, pH 8.0) followedby 0.5 CV of buffer B at a flow rate of 0.8 ml/min. Reequilibration forthe next run was performed by using 6 CV of buffer A and a flow rate of1.0 ml/min.

14.4.2 Materials and Methods

Equipment: ÄKTA explorer 10 (Amersham Pharmacia Biotech), with: PumpP-903 Mixer M-925, with 0.6 ml chamber Monitor UV-900, with 10 mm flowcell Monitor pH/C-900 Pump P-950 (sample pump) Software Unicorn Version3.21 Column: Amersham Biosciences C 10/10 Column material: Q-SepharoseFast Flow, Code no. 17-0510-01, Lot no. OD 06453 Column volume: 3 mlBuffer A: 20 mM Tris/HCl, pH 8.0, Lot-Nr. PL0746 Buffer B: 0.3M NaCl in20 mM Tris/HCl, pH 8.0, Lot-Nr. PL0747 Buffer C: 1.5M NaCl in 20 mMTris/HCl, pH 8.0, Lot-Nr. PL0748Method

Volume Step Buffer Flow rate 1 CV Equilibration 100% buffer A 1.0 ml/min5-28 ml Load sample sample 1:10 in 1.0 ml/min buffer A 10 ml Wash samplepump 100% buffer A 1.0 ml/min 5 CV Wash out unbound 100% buffer A 1.0ml/min sample Start Fractionation 100% buffer A 1.0 ml/min 6 CV Elution,linear 0-100% buffer B 0.8 ml/min gradient 2 CV Elution, isocratic 100%buffer B 0.8 ml/min 2 CV Regeneration 100% buffer C 0.8 ml/min 0.5 CVRegeneration 100% buffer B 0.8 ml/min Stop Fractionation 100% buffer B0.8 ml/min 5 CV Reequilibration 100% buffer A 1.0 ml/min Detection: 280nm, 260 nm, 220 nm pH Conductivity Fractionation: 1 ml fractions14.4.3 Results14.4.3.1 Sample According to Example 14

sample composition: 1 mg EP2001 (rhIFN-a2b) in 25 mM Na-phosphate, 0.13MCl and 0.3 mM EDTA, pH 7.5 ± 0.2 starting volume: 0.5 ml, diluted 1:10in buffer A = 5 ml flow-through/wash 9.3 ml run date: 2004 Sep. 29 runno.: QS24 D39 (see Table for example 14.4.4.114.4.3.2 Sample Accordino to Example 14.3.2 (Entry A)

sample composition: 2.5 mg EP2001 + 97.5 mg AldehydoHES10/0.4 (NZA256)0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume: 2.5ml, diluted 1:10 in buffer A = 25 ml flow-through/wash: 44 ml run date:2004 Sep. 29 run no.: QS25 D56 (see Table for example 14.4.4.1)14.4.3.3 Sample According to Example 14.3.2 (Entry B)

sample composition: 2.5 mg EP2001 + 97.5 mg AldehydoHES10/0.7 (NZA235A)in 0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume:2.5 ml, diluted 1:10 in buffer A = 25 ml flow-through/wash: 41 ml rundate: 2004 Sep. 30 run no.: QS26 D57 (see Table for example 14.4.4.1)14.4.3.4 Sample According to Example 14.3.2 (Entry C)

sample composition: 2.5 mg EP2001 + 292 mg AldehydoHES30/0.4 (NZA328) in0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume: 2.5ml, diluted 1:10 in buffer A = 25 ml flow-through/wash: 42 ml run date:2004 Sep. 30 run no.: QS27 D58 (see Table for example 14.4.4.1)14.4.3.5 Sample According to Example 14.3.2 (Entry D)

sample composition: 2.5 mg EP2001 + 292 mg AldehydoHES30/0.7 (NZA329) in0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume: 2.5ml, diluted 1:10 in buffer A = 25 ml flow-through/wash: 40 ml run date:2004 Sep. 30 run no.: QS28 D59 (see Table for example 14.4.4.1)14.4.3.6 Sample According to Example 14.3.2 (Entry E)

sample composition: 2.5 mg EP2001 + 487 mg AldehydoHES50/0.4 (NZA303) in0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume: 2.7ml, diluted 1:10 in buffer A = 27 ml flow-through/wash: 50 ml run date:2004 Sep. 30 run no.: QS29 D60 (see Table for example 14.4.4.1)14.4.3.7 Sample According to Example 14.3.2 (Entry F)

sample composition: 2.5 mg EP2001 + 487 mg AldehydoHES50/0.7 (NZA309) in0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume: 2.6ml, diluted 1:10 in buffer A = 26 ml flow-through/wash: 50 ml run date:2004 Sep. 30 run no.: QS30 D61 (see Table for example 14.4.4.1)14.4.3.8 Sample According to Example 14.3.2 (Entry G)

sample composition: 1.7 mg EP2001 + 98 mg HES10/0.4 (Supramol Lot. 407B)in 0.1M Na-acetate, 20 mM Na- cyanoborohydride, pH 5.0 starting volume:2.5 ml, diluted 1:10 in buffer A = 25 ml flow-through/wash: 42 ml rundate: 2004 Oct. 01 run no.: QS31 D62 (see Table for example 14.4.4.1)14.4.4 Comparison of the Results14.4.4.1 SDS-PAGE Analysis of IFN-Alpha Elution Peaks

Table for Example 14.4.4.1: Comparison of the Peak Areas Detected at 280nm During Q-Sepharose Chromatography of HESylated IFN-α

Calculated Eluate Area (280 nm)/ Calculated yield applied amount ofEluate mg unmodified total protein [mg] unmodified Area (280 nm) Protein(HPLC-Quantification at Run no. IFN-α [mAU × ml] [mAU × ml × mg−1] 280nm*) QS-24 1.0 mg 961 961 0.42 D39 QS-25 2.5 mg 4370 1748 1.20 D56 QS-262.5 mg 5669 2268 1.64 D57 QS-27 2.5 mg 3350 1340 1.60 D58 QS-28 2.5 mg2854 1142 1.54 D59 QS-29 2.5 mg 2255 902 1.52 D60 QS-30 2.5 mg 9278 37113.44 D61 QS-31 1.7 mg 1918 1128 1.40 D62 *data of quantitative analysisderived from RP-HPLC-3

Example 15 Description of IFN Alpha Antiviral Activity Bioassay

Description of the Test Procedure: Antiviral activity ofInterferon-alpha After pre-diluting the Test Items in cell culturemedium, serial two-fold dilutions were prepared. In 96 well microtiterplates, diluted Interferon was added—in four-fold replicate perdilution—to freshly trypsinized MDBK cells (40.000 cells per well). Theassays were incubated for 24 hours at 37° C. (total volume per well: 150μL (example 15.1) or 175 μl (example 15.2, 15.3, 15.4, 15.5, 16.2,16.3)).

Subsequently, 50 μL diluted VSV stock solution were added to each well(except for the positive control wells) resulting in a multiplicity ofinfection of 0.1.

The following controls were included in each assay: 12 wells thatreceived virus plus cell culture medium instead of Interferon (negativecontrol) and 12 wells that received cell culture medium instead ofInterferon and virus (positive control).

The assays were incubated for 42 hours at 37° C. At the end of theincubation period the cell culture supernatant of each well was replacedwith 50 μL of a solution of MTT (at least 2 mg/mL in cell culturemedium). The cells were incubated for three hours. The purple formazandye formed by the proliferating cells was solubilized by adding 100 μLsolution of isopropanol/HCl (isopropanol with 40 mM HCl) to each well.Subsequently, the absorbance values of the solutions were measured at570/630 nm in a microtiter plate reader.

The proliferative activity of MDBK cells grown in the presence ofInterferon and VSV was calculated for each dilution of Interferon asfollows:

$\frac{\begin{pmatrix}{\left( {{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{four}\mspace{14mu}{Interferon}\mspace{14mu}{treated}\mspace{14mu}{wells}} \right) -} \\\left( {{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{negative}\mspace{14mu}{control}} \right)\end{pmatrix}*100}{\begin{matrix}{\left( {{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{positive}\mspace{14mu}{control}}\; \right) -} \\\left( {{Mean}\mspace{14mu}{absorbance}\mspace{14mu}{of}\mspace{14mu}{negative}\mspace{14mu}{control}} \right)\end{matrix}}$The antiviral activity of Interferon-alpha was determined in fourseparate assays for each of the Test Items.

Example 15.1 Antiviral Activity of Intron® A Relative to NIH Standard

In all experiments, Intron® A (IFN-alpha 2b, Schering-Plough),calibrated against NIH-standard rhIFN-alpha 2a (NIAID, NIH, Bethesda,USA, Gxa01-901-535) was used as an internal lab reference. TheNIH-standard had a specific activity of 9,000 IU/ml. The internal labreference Intron® A had a specific activity of 8,487,000 IU/ml in thetest as described in example 15.

Proliferative activity of Intron® A compared to NIH standard rhIFN-alpha2a is shown in FIG. 33.

Example 15.2 Antiviral Activity of Mock Incubated IFN-HES Relative toUnmodified Starting Material

As described in example 14.3.4 mock incubated IFN-alpha-HES (describedin example 14.3.2, Entry G) was used as a reaction control. Theantiviral activity of the material was compared to that of unmodifiedstarting material to investigate the influence of the coupling andpurification process on the bioactivity. Mock incubation did not affectthe in vitro bioactivity of IFN-alpha.

Relative in vitro activity of mock incubated IFN-alpha-HES compared tounmodified IFN-alpha starting material is shown in FIG. 34.

Example 15.3 Antiviral Activity of IFN-Alpha-HES Conjugates Relative toIntron® A

In the assay system described in example 15, the conjugates (entries A,B, C, D, E from example 14.3.2 purified according to example 14.4) weretested compared to unmodified IFN-alpha starting material, Intron® A andPegasys (Roche). The CPE50 concentration of the materials wascalculated. All IFN-alpha-HES conjugates retained an antiviral activitywhich was substantially higher than that of Pegasys.

The relative in vitro activity of IFN-alpha-HES conjugates compared tounmodified IFN-alpha starting material, Intron® A and Pegasys is shownin FIG. 35.

Example 15.4 Antiviral Activity of IFN-Alpha-HES Conjugate Compared toIntron® A

In the assay system described in example 15, the IFN-alpha-HES conjugateof example 14.3.4 purified according to example 14.4 was tested comparedto Intron® A. The CPE50 concentration of the materials was calculated.The IFN-alpha-HES conjugate retained high antiviral activity of approx.25% compared to Intron® A.

The relative in vitro activity of IFN-alpha-HES conjugates compared toIntron® A is shown in FIG. 36.

Example 15.5 Antiviral Activity of IFN-Alpha-HES Conjugate Compared toIntron® A

In the assay system described in example 15, the IFN-alpha-HESconjugates of example 14.3.3, purified according to example 14.4 wastested compared to Intron® A and Peglntron®. The CPE50 concentration ofthe materials was calculated. The IFN-alpha-HES conjugates retained anantiviral activity of approx. 25% compared to Intron® A, which is on thesame level as the in vitro activity of PegIntron.

The relative in vitro activity of IFN-alpha-HES conjugates compared toIntron® A is shown in FIG. 37.

Example 16 In vivo Bioactivity of IFN-Alpha-HES Conjugates (PK Study inMice) Example 16.1 Influence of Mouse Serum on Assay System as Describedin Example 9

Dilutions of Interferon-alpha were prepared in cell culture medium(control) and in mouse serum (1:40 dilution and 1:80 dilution). Theassay was performed as described in example 15.

The antiviral activity of Interferon-alpha was determined in twoseparate assays for the control, for mouse serum 1:40 diluted as well asfor mouse serum 1:80 diluted. The results indicated that mouse serum at1:40 dilution and 1:80 does not affect the bioassay for antiviralactivity of Interferon-alpha.

Example 16.2 In vivo Study in Mice (I)

Antiviral activity of pooled serum was tested in the antiviral assay.Serum was collected from two mice (female BALB/c mice, aged 8 weeks) ateach time, which were sacrificed 2 h, 4 h, 12 h, and 24 h posti.v.-injection of 30 μg/kg (based on the protein content) of IFN-alphaor the IFN-alpha-HES conjugate.

The serum samples were thawed and thoroughly homogenized by vortexing(and diluted). Serial two-fold dilutions were prepared in cell culturemedium. A vial of Intron® A (diluted) was thawed and thoroughlyhomogenized by vortexing. Serial two-fold dilutions were prepared incell culture medium.

The EC50-dilutions in the CPE-assay were determined from dose responsecurves of a 1:2 dilution series as described in example 15.

The half life of the materials was determined compared to unmodifiedstarting material and Pegasys. The half life was calculated from asemi-logarithmic plot of the EC50-dilution vs. time post injection.

Antiviral activity was detected for (i) IFN-alpha-HES (example 14.3.2,entry B of the table), (ii) IFN-alpha-HES (example 14.3.2, entry D ofthe table), (iii) IFN-alpha-HES (example 14.3.4) up to 24 h. As can beseen from FIG. 38, half-life increased from (i) (approx. 3 h) over (ii)(approx 5 h) to (iii) (approx. 7 h).

For unmodified IFN-alpha, the antiviral activity of serum was too low tocalculate a serum half-life. In K. R. Reddy et al. Advanced DrugDelivery Reviews 54 (2002) 571-586 a serum half-life of IFN-alpha inrats (i.v.) of 2 h was determined.

Example 16.3 In vivo Study in Mice (II)

Antiviral activity of pooled serum was tested in the antiviral assay.Serum was collected from two mice (female BALB/c mice, aged 8 weeks) ateach time, which were sacrificed 2 h, 4 h, 12 h, and 24 h posti.v.-injection of 30 μg/kg (based on the protein content) of IFN-alphaor the IFN-alpha-HES conjugate.

The serum samples were thawed and thoroughly homogenized by vortexing(and diluted). Serial two-fold dilutions were prepared in cell culturemedium. A vial of Intron® A (diluted) was thawed and thoroughlyhomogenized by vortexing. Serial two-fold dilutions were prepared incell culture medium.

The EC50-dilutions in the CPE-assay were determined from dose responsecurves of a 1:2 dilution series as described in example 15.

The half life of the materials was determined compared to unmodifiedstarting material and Pegasys. The half life was calculated from asemi-logarithmic plot of the EC50-dilution vs. time post injection.

Antiviral activity was detected for (i) PegIntron, (ii) IFN-alpha-HES(example 14.3.3.1) and (iii) IFN-alpha-HES (example 14.3.3.2) up to 24h. As can be seen from FIG. 39, half life increased from (i) (approx.3.6 h) to (ii) and (iii) (approx. 6.5 and 6.8 h).

Example 17 In vivo Bioactivity of IFN-Alpha-HES Conjugates (PK Study inRabbits) Example 17.1 Radioactive Labeling of IFN-Alpha andIFN-Alpha-HES Conjugates

The samples used for the PK study were labeled with ¹²⁵I with theChloramine T method. Chloramine T is reacted with iodide and aninterhalogen species (I-C1) is formed. The interhalogen reacts on thearomatic ring of Tyrosine and substitutes it in o-position.

Example 17.2 Reference Experiment: Labeling of Oxo-HES 50/0.4 with 125I

In a first experimental series under the given reaction conditions itwas investigated whether trace amounts of iodine could be detected e.g.by iodine, polyiodine or polyiodide forming complexes with HES. Incomparison, oxo-HES (Mw 42.1 kD, DS=0.41) and IFN-alpha-HES (example14.3.2, entry E of table) were labeled under the same conditions andafter the purification process, radioactivity in the samples wasmeasured. According to literature amylopectine can form complexes withiodine, polyiodine or polyiodide when the helical structures have atleast 11 anhydroglucose units.

Only in the IFN-alpha-HES sample, radioactivity was detected. Thisresult proved that radioactivity was exclusively caused by covalentmodification of Tyrosine residues in of IFN-alpha but not by potentiallyphysically bound iodine, which was not removed in the purificationprocess. Oxo-HES 50/0.4 (Mw 42.1 kD, DS=0.41) can be considered asnegative control. Due to the high molecular weight and the low degree ofsubstitution in this oxo-HES species, the longest helical structureswould be expected if any are present and thus, in this case there wouldhave been the highest risk of complexation of iodine.

Example 17.3 Labelling of Interferon-Alpha with Non-Radioactive Iodine(“Cold Iodination”)

Interferon alpha was labeled with non-radioactive iodine in the samelabelling and purification process as the IFN-alpha-HES-conjugates. Inthe antiviral assay antiviral activity was retained. However, noquantification was performed, because in the labelling and purificationprocess the concentration was changed and could not be determined due tothe small amount of material available.

Example 17.4 Radioactive Labeling of IFN-Alpha-HES Conjugates

Samples were labeled according to example 17.1 with radioactive ¹²⁵I.The samples were IFN-alpha starting material, IFN-alpha-HES (example14.3.2, entry D of table). The samples had a specific activity of 38μCi/μg (IFN-alpha starting material), 41 μCi/μg (IFN-alpha-HES 30/0.7).

Example 17.5 In vivo PK Study in Rabbits Example 17.5.1 ExperimentalProcedure

The test items were used as a dilution. A solution of 4 μCi/ml wasprepared. Dilution buffer was PBS.

Four New Zealand White Rabbits HsdIf:NZW. Source Harlan Winkelmann GmbH,D-33178 Borchen, Sex: female; body weight at the commencement of thestudy: >2.5 kg. All animals have been applicated intraveneously with theradiolabelled test substances, receiving a volume of 1 ml/kg bodyweight, which is equivalent to a dosage of 4 μCi/kg body weight. Bloodsamples have been taken at defined time points. At each sampling pointapprox. 600 μl blood from the auricular vein of the animals was takenfor further investigations.

For the blood sampling an intravenous indwelling catheter was layedunder general anaesthesia (Ketamin/Rompun) into the auricular vein.Anaesthesia rested for the blood sampling point before application, forthe application itself and the first three blood samplings afterapplication (0.5 hours, 1 hour, and 2 hours). Catheters were let intoanimals for the further sampling points until they were excised by theanimals themselfes. Further blood samplings were determined with acannula through different areas of the auricular veins.

Further processing of the blood samples was performed after bloodsampling. To determine the radiolabelled test item in the blood, thecollected blood samples were processed according to a specificsolubilization protocol. For this 250 μl of the blood samples weretransferred to a new vial and an equal volume of Solvable™ was added.The samples were incubated for one hour at 50° C. in a shaking waterbath. After the incubation time the samples were cooled to roomtemperature and 100 μl of EDTA-solution [100 mM] was added. Subsequent300 μl of H₂O_(2 [)30%] was added and after shaking again the sampleswere incubated for one hour at 50° C. in a shaking water bath. Beforefurther processing the samples were collected.

At the end of blood collecting and solubilization the samples weretransferred to a 20 ml scintillation vial and 10 ml of the scintillationcocktail Ultima Gold™ was added. Until measurement of the isotop ¹²⁵I ina scintillation-counter (about 72 h after cocktail addition) the sampleswere stored in the dark at 2-8° C.

Prior to the processing and statistical analysis of the data the quenchof the activity detection under the specific experimental conditions wasdetermined. The regression coefficient (r²=0.9970) is a measure of thefit to the line. The quench factor [pCi/cpm] was found to be 3.315938.

Results (see FIG. 40):

IFN-alpha-HES showed a distinct prolongation of half-life compared tothe starting material. Beyond 24 h (approx. <1000 pCi/ml) the curve ofthe unmodified material leveled off and almost no decrease of activitywas observed. The small standard deviation of the measured radioactivityfor all samples proves the quality of the experiment.

The half-life was calculated from the concentration of IFN-alpha in theblood samples. For the evaluation shown in FIG. 41, only the data fromblood samples taken between 4 and 24 h were considered. For theunmodified material a half-life of 7 h was calculated. WithIFN-alpha-HES, a substantial increase of half-life was observed (approx.33 h).

Data were evaluated statistically according to different compartmentmodels as shown in the diagrams in FIG. 42 a, and b (cut-out 0-12 h). Inthe one-compartment model, it is obvious, that the concentration ofIFN-alpha rapidly drops during the first 2 hours after injection. ForIFN-alpha-HES the half-life is clearly prolonged. Statisticallycalculated half-life was 0.26 h for IFN-alpha, 7.7 h for IFN-alpha-HES.According to the non-compartment model the statistical evaluationresults in a half-life of 147 h for unmodified IFN-alpha (based on data24-120 h), 42.7 h for IFN-alpha-HES (based on data 36-120 h). Asdescribed above the half-life of the unmodified IFN-alpha issubstantially prolonged since the curve levels off beyond 24 h.

The half life of the two samples is summarized in the following table,based on the described models for the calculation.

Table of example 17.5.1

Half-Life of IFN-Alpha and IFN-Alpha-HES Calculated According toDifferent Models

IFN-alpha starting material IFN-alpha-HES t_(1/2) t_(1/2) noncompartment model (147.0*) 42.7** one compartment model 0.26 7.7 Semilogarithmic plot 7 33 (see FIG. 40, 4-24 h) *evaluated data 24-120 h,**evaluated data 36-120 h

Example 18.1 Synthesis of Amino Functionalized Hydroxyethyl Starch

Oxo-HES (Mw=41,000 D, DS=0.76) was prepared by Supramol ParenteralColloids GmbH, Rosbach-Rodheim, D; according to DE 196 28 705 A1.

To a solution of 0.51 g oxo-HES (19.15 μmol) in 2 ml dry dimethylsulfoxide (DMSO, Acros Organics BVBA, Geel, B) was added dropwise undernitrogen 200 μl (19.9 mmol) 1,4-diaminobutan (Acros Organics BVBA, Geel,B) and the mixture was stirred for 24 h at 70° C. The reaction mixturewas added to 20 ml cold acetone (0° C.). The resulting precipitate wasseparated by filtration, washed with 40 ml acetone and re-dissolved in20 ml water. The solution was dialysed for one day against water(Snake-Skin dialysis tubing, 4-6 kD cut off, Perbio Science DeutschlandGmbH, Bonn, D) and lyophilized. The yield was 80% (0.41 g) amino-HES.

The purification of the product was achieved by application to HiPrep26/10 Desalting column (100 mm, Amersham Biosciences) using an ÄKTAexplorer system (Amersham Biosciences). Therefore, the HiPrep 26/10Desalting column is equilibrated with 0.1 M NaCl solution (10 ml/min)and the amino-HES in 0.1 M NaCl (5 mg/ml, volume of injection 10 ml) wasapplied. The pooled amino-HES fractions were applied to the HiPrep 26/10Desalting column equilibrated with water (injection volume 10 ml). Thepooled HES fractions were reapplied in the same conditions to thecolumn. The pure product was lyophilized and the amine amount wasdetermined by derivatisation with 2,4,6-trinitrobenzene sulfonic acid(TNBSA (Pierce), Instructions TNBSA product number 28997) and Boc-Lys-OHfor the calibration. The amine amount was found to be 34.02 nmol/mg(92%)

Example 18.2 Synthesis of Iodoacetyl Functionalized Hydroxyethyl Starch

To a solution of 101.9 mg amino functionalized hydroxyethyl starch(amino-HESμmol as prepared in example 18.1) in 5 ml 0.1 M Na2CO3(pH=8.3) was given 12.63 mg iodoacetic acid N-hydroxysuccinimide ester(44.65 μmol, Sigma, Taufkirchen, Germany). The mixture was stirred atroom temperature in the dark under nitrogen for 15 h. 15 ml water wasgiven into the aqueous solution and the purification of the product wasachieved by application to HiPrep 26/10 Desalting column (AmershamBiosciences). Therefore, a column of HiPrep 26/10 Desalting (100 mm) isequilibrated with 0.1 M NaCl solution (10 ml/min) and the iodoacetylfunctionalized hydroxyethyl starch was applied (injected volume 10 ml).The pooled iodoacetyl-HES fractions were applied to the HiPrep 26/10Desalting column equilibrated with water and the pooled fraction werereapplied in the same conditions to the column. The pure product waslyophilized and the iodoacetyl amount was indirect determined by aminequantification with 2,4,6-trinitrobenzene sulfonic acid as describedabove. The amine amount was found to be 1.65 nmol/mg corresponding to aniodoacetyl amount from 32.37 nmol/mg (95%).

Example 18.3 Synthesis of MaleimidoHES from AminoHES of Example 18.1

25 mg of amino HES (prepared as described in example 18.1) with acalculated amino-content of ˜29 nmolmg-1, were dissolved in 450 μlreaction buffer (0.1 M sodium phosphate, 150 mM NaCl, 5.0 M EDTA, pH7.0). Separately 9 mg of N-[a-Maleimidoacetoxy]succinimide ester (AMAS,Aldrich, Sigma-Aldrich Chemie GmbH, Taufkirchen, D) were dissolved in200 μl of dry DMSO (Acros Organics BVBA, Geel, B). The two solutionswere pooled together.

The final solution was left under stirring for 100 min at 22° C. and forfurther 20 min at 40° C. The resulting solution was then diluted up to 5ml and applied on a desalting column using an ÄKTA Explorer system(Amersham Biosciences) in order to eliminate the non-reacted AMAS, NHSand DMSO.

Therefore, a HiPrep 26/10 Desalting Column (100 mm, AmershamBiosciences) was equilibrated with the reaction buffer (0.1 M sodiumphosphate, 150 mM sodium chloride, 5 mM EDTA, pH 7.0) and themaleimido-HES solution was injected (volume of injection 5 ml) andfractionated. The purification parameters were chosen as follow:

Column: HiPrep 26/10 Desalting Flow rate: 10 ml/min Eluent: 0.1M sodiumphosphate buffer, 150 mM sodium chloride, 5 mM EDTA, pH = 7.0 Samplevolume: 5.0 ml Eluate fractionation: 2.5 ml Equilibration: 0.5 columnvolumes Length of elution: 2.0 column volumes

The pooled HES fractions (7 ml) were re-injected under the sameconditions to ensure the absence of AMAS, NHS and DMSO in the finalsolution. The second purification yields 10 ml of pure MaleimidoHESready for coupling with alpha1AT.

The eluted polymer was thereafter concentrated to a final volume of 250μl in the same buffer.

Example 18.4a Reduction of alpha1AT with DL-Dithiothreitol (DTT)

To a solution of alpha1AT solution (c (alpha1AT)=5.0 mg in 0.5 ml 0.1 Msodium phosphate buffer, 150 mM sodium chloride, pH 7.2, alpha1AT=rhalpha1AT provided by GTC Biotherapeutics Inc., Framingham, Mass., lotNo. 080604A) was added 4 ml of the reaction buffer (0.1 M sodiumphosphate buffer, 150 mM sodium chloride, 5 mM EDTA, pH=7.0) and 68.77mg DTT (Sigma Taufkirchen, Germany). The mixture was incubated at 20° C.for 2 h and the reduced protein was purified by size exclusionchromatography (SEC) using ÄKTA explorer system (Amersham Biosciences).Therefore, a HiPrep 26/10 Desalting Column (100 mm, AmershamBiosciences) was equilibrated with 0.1 M sodium phosphate buffer, 150 mMsodium chloride, 5 mM EDTA, pH=7.0 solution and the reduced proteinsolution was applied (volume of injection 4.5 ml) and fractionated. Thepurification parameters were chosen as outlined below:

Column: HiPrep 26/10 Desalting Flow rate: 10 ml/min Eluent: 0.1M sodiumphosphate buffer, 150 mM sodium chloride, 5 mM EDTA, pH = 7.0 Samplevolume: 4.5 ml Eluate fractionation: 2.5 ml Equilibration: 0.5 columnvolumes Length of elution: 2.0 column volumes

The pooled protein fractions (8 ml) were re-injected in the sameconditions to assure the absence of DTT in the protein solution. Thesecond purification yields 10 ml of pure reduced α1AT solution with anapproximate concentration of 0.5 mg/ml and was used for coupling withmaleimido HES as described in Example 18.5.

Example 18.4b Pre-Treatment of 1AT with ImmobilizedTris-(2-carboxyethyl)-Phosphin-Hydrochlorid (TCEP) and Isolation ofThiol Containing Protein

alpha1AT (GTC Biotherapeutics Inc., Framingham, Mass., lot No. 080604A)was freshly treated with immobilized TCEP (Pierce 77712, 2 ml gel slurryper mg protein) in order to reduce potential disulfide bonds.Immobilized TCEP was prepared as described by the manufacture using abuffer pH=7.0 (100 mM sodium phosphate, 150 mM sodium chloride and 5 mMEDTA). Reduction was performed according to the manufacturer'sinstructions.

The reduced protein was incubated with thiol-activated sepharose(Amersham Biosciences 71-7106-00; 0.15 g gel per mg protein) in order tobind thiol containing protein covalently. Unbound protein was washed outwith a buffer containing 100 mM sodium phosphate, 150 mM sodium chlorideand 5 mM EDTA, pH=7 until no protein was detectable in the eluat. Forthe proteine detection a BCA-assay was employed (Pierce). Protein boundto the column was released and eluted using a buffer pH=7.0 (100 mMsodium phosphate, 150 mM sodium chloride and 5 mM EDTA) containing 20 mMTCEP.

Example 18.5 Preparation of HES-Alpha1AT Conjugate from MaleimidoHES ofExample 18.3 via Cysteine Coupling

725 nmol of MaleimidoHES (prepared as described in example 18.3)dissolved in 250 μl of reaction buffer (0.1 M sodium phosphate, 150 mMNaCl, pH 7.0) were added to 1540 μl of a 0.5 mgml-1 alpha1AT solution inthe same buffer. The protein was pre-incubated with DTT as described inexample T8/4a). The reaction was stirred at 22° C. for 18 h, thenstopped by freezing under liquid nitrogen and stored at −80° C. Thereaction mixture was analysed by gel electrophoresis (see FIG. 43).

Example 18.6 Preparation of HES-1AT Conjugate from IodoacetamidoHES ofExample 18.2 via Cysteine Coupling

96 mg of IodoacetamideHES (prepared as described in example 18.2) with acalculated iodine content of ˜16 nmolmg-1, were dissolved in 1.0 mlreaction buffer (1.0 M sodium carbonate, 2.0 mM EDTA, pH 8.3) and 2.5 mldistilled water. 500 μl of a 3 mgml-1 alpha1AT (pre-treated as describedin example 18.4b) solution in 0.1 M sodium phosphate buffer, 150 mM NaCl(pH 7.0), were mixed with the polymer solution and finally 500 μl of asolution containing 7.2 mg of TCEP (Aldrich, Sigma-Aldrich Chemie GmbH,Taufkirchen, D) were added to yield a 5 mM final concentration of thereducing agent. The reaction was allowed to proceed under lightexclusion and stirring, for 18 h at room temperature. Thereafter it wasstopped by freezing under liquid nitrogen and stored at −80° C.

Example 18.7 Purification of HES-Alpha1AT Conjugate Prepared fromIodoacetamidoHES of Example 18.2 via Cysteine Coupling

Sample preparation: buffer exchange on a HiPrep 26/10 Desalting column(Amersham biosciences) in combination with the ÄKTA-Explorerchromatography system using 20 mM sodium phosphate, 20 mM sodiumchloride, pH 8 as eluent.

Buffer exchange was performed with the crude reaction mixture(preparation as described in example T8/6, approximately 4 ml) using thefollowing parameters:

Column: HiPrep 26/10 Desalting Flow rate: 10 ml/min Eluent: 20 mM sodiumphosphate, 20 mM sodium chloride, pH 8 Sample volume: 10 ml Eluatefractionation: 2.5 ml Equilibration: 5 column volumes Length of elution:2 column volumes

Fractions from 6 to 16 ml were pooled. Excess of HES-derivatives wereeliminated by IEC using the following parameters:

Column: HiTrap Q HP 1 ml Flow rate: 1 ml/min Binding Buffer (BB): 20 mMsodium phosphate, 20 mM sodium chloride, pH 8 Elution Buffer (EB): 20 mMsodium phosphate, 1M sodium chloride, pH 8 Empty loop with: 12 ml Flowtrough fractionation: 2 ml Eluate fractionation: 1 ml Startconcentration EB: 0% Equilibration: 5 column volumes Wash out unboundsample: 15 ml Target concentration EB: 15% Length of gradient: 50 ml

Fractions from 43 to 73 ml were collected and concentrated to a finalvolume of 10 ml by ultracentrifugation. After desalting as describedabove (sample volume 10 ml, collected fractions contain the first 14 ml)a second IEC for separation of conjugate from unbound protein wasperformed using the following parameters:

Column: HiTrap Q HP 1 ml Flow rate: 1 ml/min Binding Buffer (BB): 20 mMsodium phosphate, 20 mM sodium chloride, pH 8 Elution Buffer (EB): 20 mMsodium phosphate, 1M sodium chloride, pH 8 Empty loop with: 15 ml Flowtrough fractionation: 2 ml Eluate fractionation: 1 ml Startconcentration EB: 0% Equilibration: 1 column volumes Wash out unboundsample: 2 ml Gradient: 5-15% Length of gradient: 100 ml

The following fractions were collected and analysed by SDS-Page (seeFIG. 44):

A: 26-32 ml B: 37-45 ml C: 55-65 m

OTHER EMBODIMENTS

It is to be understood that while the invention has been described inconjunction with the detailed description thereof, the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the scope of the appended claims. Otheraspects, advantages, and modifications are within the scope of thefollowing claims.

What is claimed is:
 1. A conjugate comprising a protein and a polymerderivative, wherein the polymer is a hydroxyalkyl starch (HAS) and theprotein is selected from the group consisting of IFN beta, GM-CSF, APC,tPA, A1AT, AT III, factor VII, factor VIII, and factor IX, saidconjugate having a structure according to the formula

wherein R₁, R₂ and R₃ are independently hydrogen or a hydroxyalkylgroup, or hydrogen or a hydroxyethyl group, wherein, in the conjugate,HAS is bonded at its non-oxidized reducing end to a bifunctional linkingcompound, and the bifunctional linking compound is bonded to an oxidizedcarbohydrate side chain or an oxidized N-terminal group of the protein,wherein HAS′ is the remaining part of the starch molecule HAS, andwherein L is a substituted or unsubstituted, linear, branched and/orcyclic hydrocarbon residue, optionally comprising at least oneheteroatom.
 2. The conjugate of claim 1, wherein -L- is—[(CR_(a)R_(b))_(m)G]_(n)[CR_(c)R_(d)]_(o)— wherein R_(a), R_(b), R_(c),and R_(d) are independently hydrogen, alkyl, aryl, wherein G is selectedfrom the group consisting of O and S, wherein m is 1, 2, 3 or 4, whereinthe residues R_(a) and R_(b) may be the same or different in the mgroups CR_(a)R_(b); wherein n is 0 to 20; wherein o is 0 to 20, whereinthe residues R_(c) and R_(d) may be the same or different in the ogroups CR_(c)R_(d); and wherein n and o are not 0 at the same time. 3.The conjugate of claim 2, wherein R_(a), R_(b), R_(c), and R_(d) arehydrogen, m is 2, n is 1, and o is
 2. 4. The conjugate of claim 1,wherein the hydroxyalkyl starch is hydroxyethyl starch.
 5. The conjugateof claim 4, wherein the hydroxyethyl starch has a molecular weight offrom 2 to 200 kD.
 6. A pharmaceutical composition comprising one or moreconjugates of claim 1 and a pharmaceutically acceptable diluent,adjuvant, or carrier, wherein the protein is IFN beta.
 7. The conjugateof claim 1, wherein the protein is IFN beta.
 8. The conjugate of claim1, wherein the protein is GM-CSF.
 9. The conjugate of claim 1, whereinthe protein is APC.
 10. The conjugate of claim 1, wherein the protein istPA.
 11. The conjugate of claim 1, wherein the protein is A1AT.
 12. Theconjugate of claim 1, wherein the protein is AT III.
 13. The conjugateof claim 1, wherein the protein is Factor VII.
 14. The conjugate ofclaim 1, wherein the protein is Factor VIII.
 15. The conjugate of claim1, wherein the protein is Factor IX.
 16. A pharmaceutical compositioncomprising the conjugate of claim 1, wherein the protein is GM-CSF. 17.A pharmaceutical composition comprising one or more conjugates of claim1 and a pharmaceutically acceptable diluent, adjuvant, or carrier,wherein the protein is APC.
 18. A pharmaceutical composition comprisingone or more conjugates of claim 1 and a pharmaceutically acceptablediluent, adjuvant, or carrier, wherein the protein is tPA.
 19. Apharmaceutical composition comprising one or more conjugates of claim 1and a pharmaceutically acceptable diluent, adjuvant, or carrier, whereinthe protein is A1AT.
 20. A pharmaceutical composition comprising one ormore conjugates of claim 1 and a pharmaceutically acceptable diluent,adjuvant, or carrier, wherein the protein is AT III.
 21. Apharmaceutical composition comprising one or more conjugates of claim 1and a pharmaceutically acceptable diluent, adjuvant, or carrier, whereinthe protein is Factor VII.
 22. A pharmaceutical composition comprisingone or more conjugates of claim 1 and a pharmaceutically acceptablediluent, adjuvant, or carrier, wherein the protein is Factor VIII.
 23. Apharmaceutical composition comprising one or more conjugates of claim 1and a pharmaceutically acceptable diluent, adjuvant, or carrier, whereinthe protein is Factor IX.
 24. A method comprising administering theconjugate of claim 1 to a human or animal in need thereof, wherein thehuman or animal is in need of treatment for multiple sclerosis, andwherein the protein is IFN beta.
 25. A method comprising administeringthe conjugate of claim 1 to a human or animal in need thereof, whereinthe human or animal is in need of treatment for thrombosis,thromboembolism or occlusive arterial diseases, and wherein the proteinis APC.
 26. A method comprising administering the conjugate of claim 1to a human or animal in need thereof, wherein the human or animal is inneed of treatment for myocardial infarction, thrombosis, thromboembolismor occlusive arterial disease, and wherein the protein is tPA.
 27. Amethod comprising administering the conjugate of claim 1 to a human oranimal in need thereof, wherein the human or animal is in need oftreatment for emphysema, cystic fibrosis, atopic dermatitis, orbronchitis, and wherein the protein is A1AT.
 28. A method comprisingadministering the conjugate of claim 1 to a human or animal in needthereof, wherein the human or animal is in need of treatment forveno-occlusive disease, disseminated intravascular coagulation, orsepsis, and wherein the protein is AT III.
 29. A method comprisingadministering the conjugate of claim 1 to a human or animal in needthereof, wherein the human or animal is in need of treatment forhemophilia A, and wherein the protein is Factor VIII.